Try Coyote Lake: This is a Santa Clara County park. A very pretty campground with two areas - a hookup loop and a drycamp loop. Some of the campsites are large and spread out. Some campsites are next to the water so you can walk down to the water and setup lawnchairs there and be only around 100 feet from your rig.
County parks can be a good go-to choice.
Also try Lake Amador Resort in the Sierra Foothills: This is a private park that's on a large private lake. The park is huge - spread out over rolling hills around the lake with large isolated sites. It's old, so some sites have only 20 amp hookups that take a special adaptor that you rent at the store. You can launch a boat (or rent) and beach it a few yards from some of the sites and keep it there for several days use while camped.