you "can" camp right on the river across from the hatchery, now, i won't say you "should" due to the amount of local punk teenagers and other assorted bottom feeders partying on the gravel bar, but it used to be a decent place to camp out years ago.
promised land campground is right up the road a couple miles past the store off the highway. haven't stayed there myself but it doesn't look like a bad place.
humptulips summer runs are definitely a fish you have to put your time in for.