There are a few RV parks between SF and Bodega in Marin County, unfortunately I can't speak to how nice they are as we haven't stayed at them. A quick Google search will bring them up.
We have stayed in Bodega itself. We stayed at Bodega Bay RV Park and its decent. Gravel sites, full hook-ups and decent space between rigs. There are also a couple others in Bodega, some with limited or no hook-ups.
There is also a KOA in Petaluma that I hear is nice. Its inland from the coast, just off the 101. The drive from there to Bodega is probably 30-40 minutes, maybe.