M.M.
Hi M.,
I don't know where you have already been , but some local campgrounds we love are San Clemente State Beach, Campland on the Bay (Mission Bay in San Diego), Chula Vista RV Resort, Prado Regional Park (Chino), O'Neil Regional Park, Calico Ghost Town is fun during Halloween, Lopez Lake (this is about 5 hours away in San Luis Obispo county), Caspers Regional Park, and Lake Casitas near Ojai (you can't go in the lake, but they do have a waterpark.)
I do not like to be disappointed when I arrive at a new campground, so I usually do a drive through before making reservations so that I get a good spot. Most parks will let you in for 15 minutes for free.
Happy Camping!!