I hate to post this as some day I'll arrive to find my spot taken. We just arrived this afternoon at Hatchet USFS CG that is 10 miles E of Moran Junction. $10/night but only $5 with the Old Fart Pass. There is water (bring a long hose) but only one site big enough for a big rig and I'm able to get Sat TV from it. No dump station so you wold have to figure that out for long term. The mosquitoes are pretty bad so I'd get out my fogger if I was staying any length of time. Had dinner at the Hatchet Resort next door so I could get the code to their "guest" WiFi which I'm using to post this.
There are several USFS CGs north of here on the river but pretty sure there is not any water.