Tourists squeeze through the church-like pews of Nashville's Ryman Auditorium, snapping photos of the country music shrine, oblivious to the 73-year-old man on stage, silently putting the finishing touches on his latest script.

As the crew for "A Prairie Home Companion" tinkers with the lights and a barbershop quartet runs through a number, their outgoing boss could be wolfing down a pork-shoulder sandwich at Jack's Bar-B-Que across the back alley or tapping his hairy knuckles to Merle Haggard tunes at nearby Tootsies Orchid Lounge.

Instead he is sitting in his stocking feet in a folding chair behind a Hammond organ, hunched over his laptop, crafting and re-crafting every single word for his radio show, just as he has 1,548 times before.

It's an implausible scene, the writer up against a tight deadline, eschewing his quiet hotel room just three blocks away to work amid the chaos, but it neatly captures the two polar sides of Garrison Keillor — the ringmaster who could turn the Salem witch trials into a singalong and the shy bookworm who would escape chores as a kid to read on the toilet.

"I think he's the Mark Twain of our generation, and that's no small statement," says country music superstar Brad Paisley, who became obsessed with "Prairie Home" while growing up in West Virginia and has raised his two boys on the program's goofy sound effects and G-rated jokes.

Shari L. Gross
Video (03:00) Singing harmony is what Garrison Keillor loves to do on A Prairie Home Companion, so we spoke with some of the women he loves to perform with.

Now the curtain is dropping on one of the most influential, improbable and demanding acts of the past half century.

Keillor has tried slowing down before, musing aloud about semi-retirement and going so far as to throw a farewell party to "PHC" in 1987. He was back on the air in 26 months.

This time, friends and colleagues are convinced he means it. Spurred by health problems — he recently began taking medication to prevent seizures — and a fear of overstaying his welcome, he will abandon the weekly grind two weeks from now with a final show at the Hollywood Bowl. Then he'll take a three-day train ride from Los Angeles to his St. Paul home to reflect on his future plans, including a screenplay, a memoir and a newspaper column.

"You come to the realization that you want to get some part of a normal life back," he says.

But at the moment, there's a show to prepare.

On this Friday afternoon, his fingers fly across the keyboard, slowing only to google the lyrics to the George Jones-Tammy Wynette duet "We're Not the Jet Set" and a list of the world's greatest philosophical questions. He'll employ both in a new adventure for Guy Noir, one of several universally beloved Minnesotans born and bred in his imagination.

As for his weekly tour of Lake Wobegon, the signature monologue that launched a cottage industry and has been spoofed on "The Simpsons"?

"Haven't started it," he says without looking up from the screen.

It is 25 hours to air.

The rebel

It all started at the Ryman. At least that's what Keillor will tell his audience there the following evening. Assigned by the New Yorker magazine to write a story about the Grand Ole Opry moving to a shinier new building in 1974, he was inspired to launch his own variety show back home.

Minnesota Public Radio founder Bill Kling remembers things a little differently. Kling had taken a shine to Keillor the moment the recent University of Minnesota grad stepped into his office in 1969, dressed in bell-bottom pants, granny glasses and a flowery shirt, hoping to nab a position as morning DJ for tiny classical station KSJN.

Keillor was a latecomer to classical music, having grown up singing hymns around the parlor piano in a strict Christian household where Mozart was as forbidden as Elvis Presley.

"My interest came during college from trying to impress women," said Keillor last month in his St. Paul office, shortly before being interrupted by a ring from his cellphone — a snippet from a Puccini opera.

"Instead of owning a shotgun and going duck hunting, you go to the St. Paul Chamber Orchestra and meet a different class of women."

It didn't take long for the newbie to push the envelope. Kling remembers a shift in which the guests included a cowboy singer and a guy who made music by rubbing wine glasses.

"He called me afterward and said, 'What did you think?' " Kling said. "I told him it was one of the worst mornings I could remember."

But Kling thought the freewheeling format might work in front of a live audience. Perhaps early Saturday evenings?

The conductor

The day before a State Theatre performance last month, Keillor was once again stationed on stage, transcribing sketch ideas onto his computer from notes scribbled on glossy magazine pages and the back of an airline ticket receipt.

But he kept getting out of his seat during Twin Cities singer Hilary Thavis' run-through of "Baseball Blues," a ditty Keillor had whipped up to poke fun at the Minnesota Twins' foibles.

"Less, less, less," he said, insisting the band pull back so that the St. Paul singer could be heard more clearly. "If they can't hear the lyrics, they might as well be in Danish."

"Can I make a counter argument?" said the show's musical director, Richard Dworsky.

Sure. Just don't expect to win.

"It may not always work best for the band, the singer or the moment, but he usually knows what works best for the show," an unrattled Thavis said after the rehearsal.

Keillor may appear to be inside a bubble in the 48 hours before a show, a developing script in one hand, a paper cup of water in the other, but he's aware of every sound in rehearsal. He writes onstage not because he craves the company; he wants to be within earshot of the actors and musicians, in case they veer off track.

"We started off terribly, terribly polite, and that's not a good thing in this business because it places the performer's sensibilities ahead of the audience," he said. Keillor credits New York — where he has maintained an apartment in Central Park West since 1988 — for helping him shed his Midwest passivity.

Those who grew up with him, though, say he's never been timid about taking control.

Linda Keillor Berg, the youngest of six siblings, begged her 14-year-old brother to include her in a play he wrote for the neighborhood kids. He finally relented, casting her as a cat who spends the entire play sleeping under a table.

Bill Pedersen, who has known Keillor since first grade, got a lecture after turning in a story for the Sunnyvale Star, the newspaper Keillor founded at age 12.

"He said, 'Bill, you're my best friend, but this didn't come out very well. No cursive. I want it printed out,' " said Pedersen, who would grow up to call the shots at St. Peter Regional Treatment Center.

He showed a stubborn streak in his early radio days. Upset over interference from management, Keillor once spent a morning shift playing nothing but "Help Me, Rhonda."

He can be curt. Ask a personal question and he'll shoot you a penetrating stare, a weapon all the more chilling after he's spent 20 minutes in deep conversation without ever looking you directly in the eye. In the 48 hours leading up to a show, he can walk right past veteran crew members without mustering a "good morning" or a smile.

Shari L. Gross
Video (02:23) Garrison Keillor shares his reaction when he watched video of the taping of A Prairie Home Companion

"He's not an oh-my-God, tell-me-everything-about-you kind of guy. He's warm in a different way," said singer-songwriter Aoife O'Donovan, so devoted to Keillor that she's playing his L.A. show, then catching a redeye to make her wedding in New York that weekend. "You've got to look outside the box, which is sort of the underlying theme of the show."

The superstar

Although Keillor can be demanding, he's earned it.

Soon after the show began airing nationwide in 1980, he insisted on mailing a free four-color poster to loyal listeners. There were more than 10,000 requests. Kling may have grumbled about the cost, but that response — and the way 64 phone lines would light up at intermission during MPR member drives — showed he had a megahit on his hands.

Keillor appeared on the cover of Time magazine. Playgirl named him one of the sexiest men in America. "Lake Wobegon Days," the second of his 28 books, sold more than 1 million copies in 1985. And MPR became a heavyweight in the public radio world, with the "PHC" catalog of audiobooks and coffee mugs funneling millions into its operations.

"I'm in his debt for paving the way," said Ira Glass, host of the show "This American Life." "He was like our Beatles, doing something weirder first."

Big names joined the fan club. Dick Van Dyke served as warm-up act on a book tour. Tom Brokaw planned dinners around the show. Bruce Springsteen popped in backstage.

Martin Sheen's love affair with "Prairie Home" doesn't always go over well with his wife. He's been known to linger in the driveway, glued to the car radio while the couple's takeout dinner goes cold.

"Johnny Cash once said that true greatness is someone who doesn't remind you of anyone else. That's Garrison," Sheen said in a phone interview. "For the past 40 years, he's been the greatest storyteller, the most imaginative voice on the air."

During the first week of filming TV's "The West Wing," Sheen showed off his Keillor impression to his new castmates. When actress Allison Janney remarked that she had worked on "Prairie Home Companion" for two seasons, he almost fainted.

"I think that's the first time Martin took notice of me," said Janney, who played various Wobegon characters in the early 1990s before going on to collect six Emmys. "I suddenly became a superstar to him."

The wallflower

There are few mementos in Keillor's office acknowledging his international fame, aside from Kevin Kline's chair from the 2006 film "A Prairie Home Companion," shot in St. Paul. His most prized possession: A framed photo of his first-grade class.

His dressing room always includes an ironing board, so he can personally smooth out the wrinkles from an off-the-rack white shirt, still wrapped in plastic, his cuff links stored in an Altoids box.

He steers clear of details about his two previous marriages. Sure, he almost cried once on stage, after Sen. Paul Wellstone's death. Won't happen again. Not in good taste.

The closest thing to sharing a regret is his recollection of spotting a father and his young daughter sharing a tandem bike.

"It just tore my heart out because here is something I should have done," he said. He has two children, a son who works for the show and a daughter just graduated from high school in New York. "Now she's 18. I want to get it back."

Janney is surprised to learn that Keillor has started hosting cruises. "I would think he'd be terrified to be on a boat without an escape hatch," she said.

During shows, Keillor loves nothing more than wandering though the crowd, sticking the microphone in strangers' faces, encouraging them to join him in an a cappella version of "America the Beautiful." But most of the time he performs with his back to the audience. During breaks, he wanders with his head buried in his notes. No one approaches him.

"I look like somebody who is about to be shot by a firing squad," he said. "It's terrible. I'm just trying so hard to think."

Acclaimed humorist Roy Blount Jr., a longtime friend, said fans shouldn't misinterpret it as aloofness. "Sometimes people complain that they can't have a conversation with him, but I think that's because he's writing in his head."

Blount is relieved that Keillor is slowing down. Three weeks ago, Keillor was taken to the emergency room to be treated for nocturnal brain seizures. He suffered a minor stroke in 2009 and had an undisclosed surgical procedure five years later. In every case, he barely missed a day of work.

Keillor said he's looking forward to being relieved of the weekly pressures and to working in his home study, with his wife, Jenny Lind Nilsson, a violist for the Minnesota Opera, popping her head in occasionally to see how he's doing. He's hoping to complete his memoir and a screenplay, and to tackle some of the books teetering on the shelves around his desk.

Fred Newman, the show's sound-effects wizard, said that until recently his boss didn't talk much about his impending departure or the fact that his hand-picked successor, Chris Thile, will take over in the fall. But he's slowly coming around, notably in a song he debuted at the State Theatre, an unabashed love letter to his parents called "Trees."

"He started to embrace it and then celebrate it," Newman said. "And with Chris coming on from time to time this year, it's really been the perfect transition."

Fact is, no one really expects Keillor to stay away from "Prairie Home."

"It's hard to believe he won't keep a hand in it," said Blount, well aware that Keillor retains the title of executive producer. "He's going to pop up now and then. But he's tired."

An encore

It is two hours after the Nashville show and Keillor has earned a good night's sleep, having stayed up until 11:30 the night before to write his "Wobegon" monologue over a room-service meal of brown rice and steamed vegetables.

As the crew tears down the set's fake porch, he sticks around, chatting with Paisley's family, charming O'Donovan's mom and revisiting memories with the Ryman's director.

Now it is time to head back to the hotel. He walks the three blocks without an entourage, his wheeled computer bag dragging behind him. Suddenly he is spotted by a fan. Then three. Soon a few dozen people are clustered around him as he graciously poses for selfies and signs autographs with the black Sharpie he always keeps in his breast pocket.

He comes alive, prodding lifelong listeners with questions about the weather in their hometowns, offering career advice to an up-and-coming podcaster.

"Didja see the sights?" he says to one fan who traveled from Cleveland to see the show, playfully punching her in the shoulder. Hearing that one member of the flock is a German tourist, he bursts into an obscure German folk song. The visitor beams.

After 20 minutes, the crowd thins out and he arrives at the hotel. The crew and cast will gather in the upstairs bar to celebrate the retirement of the show's longtime truck driver.

Keillor won't be joining them. Instead, he orders a ginger ale on ice from the otherwise unoccupied lobby bartender and steps into the elevator, alone.

It is seven days to showtime.

Neal Justin • 612-673-7431 Twitter: @nealjustin