Treasure Island Casino must have been offering some kind of treasure.

Why else would Nik Johnson of St. Cloud have waited more than two hours in traffic? Mark Olson of Woodbury more than an hour? And “forever” for Sarah Lund of St. Paul.

The treasure was country-music institution Willie Nelson appearing Friday at the new amphitheater at Treasure Island in Welch, Minn.

It was the first in an ambitious series of nine concerts at the ad hoc amphitheater. Among those scheduled are Journey, Brad Paisley, Weezer and a comedy program featuring Adam Sandler and David Spade.

But getting 11,000 concertgoers onto the grounds of Treasure Island was challenging. The traffic was backed up for miles.

David Weidt of St. Paul spent more than an hour and a half waiting to turn from County Road 18 onto Sturgeon Lake Road, which takes you to Treasure Island. He and his girlfriend got fed up and drove on to Red Wing for dinner and didn’t use their $69 Willie tickets.

“We never saw anyone directing traffic or any other sign of organization,” said Weidt, 65, who has seen 20 Willie shows since 1975. “I don’t feel like I’m being overly sensitive when it takes an hour and half to go three miles. We decided to give up.”

Not Johnson, 25, a veteran of big rock festivals like Bonnaroo in Tennessee. “It’s worth the wait for Willie,” said the bearded dude in a Clash T-shirt.

Stacy Lufkin, 49, of Rosemount, first saw Willie at the State Fair when she was in sixth grade. She showed up Friday with a group of fellow teachers after their last day at school. They were smart enough to book rooms at the casino so Lund could stash her commemorative date-specific Willie poster (one of only 75 printed) before the music started.

The amphitheater set up is not permanent. Cars park in a giant grassy, bumpy lot. A massive stage with a roof was erected in a field, with rows and rows of plastic chairs atop crushed rock. Portables toilets are set up on either side of the stage.

During Charlie Daniels set before Willie’s, the line for the toilets was two-deep for a good 70 yards. The wait was longer than you’d probably have to get a gun permit in Willie’s home state of Texas.

Lufkin, whose husband Steve was in a wheelchair, said they would have had to go into the casino if Steve had to use the restroom. Otherwise, he was able to negotiate the venue without a problem, she said.

Concession stands were limited. There were a couple of beer booths on either side of the stage. Food — burgers, hot dogs, brats and nothing vegetarian except chips — was available in a good-sized tent that also had several picnic tables. Another stand — dubbed “convenience” — sold bug spray for $10 and snacks for $5.

Video screens were perched on both sides of the stage but they weren’t exactly jumbo. From the back row of seats, the screens looked like the size of a TV at a sports bar. And the seating area is fairly flat.

Grand Casino in Hinckley has operated an amphitheater for many years. Among the acts booked there this summer are Kiss, Rascal Flatts, Paramore and Kid Rock. Mystic Lake Casino in Prior Lake has had an amphitheater on-and-off for a few years. This year’s lineup features Lionel Richie, Santana and Blink-182.

Veteran concertgoer Olson, 56, has been to all three casino amphitheaters.

“This one has a nicer atmosphere,” he said of Treasure Island. “It’s less of the casino on top of you and more trees.”

Concertgoers might have wanted more Willie. He was onstage for less than 70 minutes. At times, the 84-year-old legend seemed short of breath and perhaps under the weather. (Or maybe he’s just acting his age, finally.)

“It wasn’t Willie’s best night,” said longtime fan Lufkin.

In the earlier part of Nelson’s set, he spoke the lyrics more so than sang them. But his voice gained musicality and strength as the set progressed. (“Georgia on My Mind” was quite memorable.) He didn’t play a great deal of guitar, instead calling upon his sister Bobbie Nelson to take several piano solos and Mickey Raphael to take over on harmonica.

Willie’s set list was about as freewheeling as his vocal phrasing. Of course, he opened with “Whiskey River,” he always does, but didn’t play such longtime favorites as “Blue Eyes Cryin’ in the Rain,” “On the Road Again,” “City of New Orleans,” “Crazy” and “Nightlife.” He offered a medley of Hank Williams rockers, Tom T. Hall’s “Shoeshine Man,” two pro-pot songs (one of which he dedicated to the late Merle Haggard) and two tunes from his commendable new album, the dark title track, “God’s Problem Child” (with lovely blues-meets-flamenco guitar by Willie) and “Still Not Dead,” a playful ditty that demands “Don’t bury me. I’ve got a show to play.”

Before Willie, Bruce Hornsby performed an hourlong set with his band, as did Charlie Daniels, who burst into his signature “The Devil Went Down to Georgia” as a full moon was rising over the stage.

Treasure Island’s staff will be meeting Monday to discuss tweaks to the concert setup.

“There will be changes that will be made,” said Amy Ransom, Treasure Island’s public relations specialist. “Guests were very open about how they felt. We’re about making sure guests have the best experience.”

Changes will be necessary, especially since Treasure Island is planning to add seating on the lawn behind the plastic chairs to increase capacity.

“Could they offer shuttle buses from the Mall of America or Red Wing High School?” wondered Lufkin.

In any case, she says she’d return to Treasure Island for an outdoor concert.

“I had a blast,” she said on Sunday. “I was thrilled to be there with my husband. It was about being there with him and friends. We’d go back. We’d have to go earlier.”