Dusty Lake would be my first choice with a tube, but NOT sure that it's currently open and also beware the hike down into it through rattlesnake country...maybe 2/3 mile? But nice Rainbows and Browns. It's in Quincy Lakes Wildlife area, lies about 3-4 miles due North from the amphitheatre. Desert pothole lakes are all through here, Evergreen Reservoir is the first one you'll come to when driving from the Gorge and is managed for spiny rays, also Stan Coffin is up the road a bit and is also managed for spiny rays (bass catch and release, small crappie and bluegill). Take road # U NW... from the vicinity of the Gorge campground it's about a mile east and follows pretty much under the powerlines due North. It's about a 10-minute drive from the amphitheatre. My family and I frequently stay at the lakes (primitive camping but better outhouses than the Gorge camground)when attending concerts, unless we want to party in which case we stay at the Gorge campground. But there are some partiers at the lakes as well, usually. Good places for a swim too if you are attending multi-day shows. Have fun!