As of 3/22/2017, the county web site shows this as closed to RV's due to road closure.
Although they do not specify an exact length, they say that anything over 30' will have a very difficult time going up the road and has to be escorted up by a ranger, regardless of your superior driving capabilities. Lol
Typical CA public park. Water and dump stations are available off site, and the showers are few but free.