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 and comedian Adam Sandler.

But getting 11,000 concertgoers onto the grounds of Treasure Island was challenging.

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 eventually 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,” he said.

The amphitheater setup 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. Portable 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.

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 with picnic tables. Another stand — dubbed “convenience” — sold bug spray for $10.

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 sports-bar TVs. 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 and Paramore. 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 on stage for less than 70 minutes. At times, the 84-year-old legend seemed short of breath and perhaps under the weather. “It wasn’t Willie’s best night,” said Stacy Lufkin, 49, of Rosemount, who first saw Nelson when she was in sixth grade.

In the earlier part of his set, he spoke the lyrics more than sang them. He offered a medley of Hank Williams rockers, two pro-pot songs and two tunes from his new album, the dark title track, “God’s Problem Child” and “Still Not Dead,” a playful ditty that demands “Don’t bury me. I’ve got a show to play.”

Treasure Island’s staff will be meeting Monday to discuss tweaks for concerts.

“Changes will be made,” said Amy Ransom, the casino’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 the casino is planning to add seating on the lawn behind the plastic chairs.

Changes or not, Lufkin says she’d return to Treasure Island for an outdoor concert.

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