How close do you need it to be to cameron park? One of my very favorite places is Bassi falls in the icehouse area. Granted you can't take the smb right up to the falls, but there's lots of camping in the area with showers etc. '
Course, the 40 minute drive on icehouse road to get back to 50, and then another 30 minutes on the freeway don't 'zactly make it close to cameron park.
Bout as far in the other direction is Folsom lake.