Hell's Canyon Campground

This is an older campground, made in the days when "canned ham" campers were big rigs. The sites are small - tenters, truck campers and maybe an R-Pod at the most would be comfortable in here. This camp sees little use compared to other camps in the area. Most sites are a little overgrown and run down. Tables are a little rotten, older wooden pit toilets and crumbling concrete fireboxes. No water and no trash. The road in is narrow and almost always muddy. The bonus is you would likely have the place all to yourself even when every other camp in the valley is packed full.
Lots of bears in the area too. There are no bear boxes in camp due to the age of the camp but you will need to observe all bear country rules and keep everything packed away securely.
And a warning in general. Main Boulder Road is very long, narrow and rough. If you're not familiar with the area I would advise to scout things out first without your RV and determine if you're comfortable driving the road with your rig. Plenty of locals make the trek up here successfully but there are a lot of narrow sections of road and not a lot of opportunity to turn around if you are towing.