Crowley Lake Everyone knows Crowley. 6000 - 8000 people show up. This lake arguably provides some of the best trout fishing in California. This is a big lake, and a boat is useful. They are available for rent.
Float tubes are common.
Try crawling all the way across the lake in a float tube. That would make a good story. Crowley Lake is just a few miles south of Mammoth on HWY 395. After August 1 thru October 31 it's two fish per day, 18-inches total length, and only artificial lures with barbless hooks can be used. Creek Spectacular scenery.