i second caddis for use as a fishing camp. nice pool for swimming right by camp, and you can walk upstream nearly 1.5 miles with good access to wade fish thru ute park. we had plenty of room for our group of 4, but it might start to get tight for more than 6-8 people and more than 3 boats.
very similar case for buttermilk too, but you would be walking downstream to access the same 1.5 mile stretch through ute park and you would be on the opposite side of the river. i don't remember seeing cowboy camp from the river, but it is by buttermilk too. the side banks of the river that buttermilk/cowboy are on have more steep rock obstructions, so you might not be able to fish the whole stretch unless you could wade across the river. i think all the other camps in ute park are designated for hikers, and not allowed for use by boaters.
i was really surprised by the number of folks on this stretch of river last summer, as most if not all the camps were full. the last time i boated it about 3-4 years before on a saturday day-trip it seemed rather empty, and i don't recall seeing many groups camping. i think the popularity of the run has really boomed, and the use is increasing significantly (future permits??). the camp sign up system currently in place seems ripe for misuse, so the suggestion to take a pic of the register when you sign in seems like a good one. later.