The cottonwood lakes are the brood stock for DFG golden trout, I am not sure what the current regs are. In past years these lakes have opened up in early July.
Basically the best golden trout fishing you can find. All barbless C&R.
http://www.dfg.ca.gov/fg_comm/2003/freshfish03.pdflooks like only cottonwood # 5 can you keep any fish, as I recall, I have not caught any there
Most of the lakes on the east syde are pretty good overall. I have made trips in the past to cottonwood as a fishing destination.
mike
almost forgot
Bead head zug bugs work great there