I generally use rvparkreviews.com to research campgrounds. There aren't that many choices near Oakland. I have stayed at Anthony Chabot Family Campground in my truck camper, and thought it was pretty nice. It's a bit of a drive up a windy road, but should be ok with a large 5th wheel. It would probably be a 10-15 minute drive to Oakland. I would avoid any RV parks within the east bay cities (ie - Richmond down to Union City) as these aren't the most pleasant places. Further east towards Concord is nicer, but I'm not sure if there are any RV parks out that way and you may get stuck in heavy commuter traffic. Is there a reason you need to be near Oakland? There are many really nice places in Marin, and in the Santa Cruz mountains, but these are a long way from Oakland.