As far as I could tell, there are about 3 pools that were holding the majority of the fish. All were down stream of the campground. My advice would be to drive along, stop at any likely-looking, slow-moving pools, and look down. If they're in there, you'll see them.
As far as flies go, I would suggest any white streamer. Just make sure you have enough weight on it to get it in the strike zone. These fish are not going to move more than a few inches to feed. You may also want to try a pellet fly.
On a side note, this is probably as close as you can get to actually fishing in a hatchery, IMHO.
Hope this helps.