OK. Based on the current weather the desert is starting again. Try Borrego Springs and Anza Borrego Desert State Park. I unhesitatingly recommend Palm Canyon RV Resort. The State Park also has a decent RV campground with full hookup sites.
Don't like the desert? Try San Diego. I like the Chula Vista RV Resort. It is adjacent to a nice city park and near a small marina.
Want a lake? We have two in range: Lake Casitas near Ojai, and Lake Cachuma near Solvang/Sta. Y?ez, north of Santa Barbara. Both are water district reservoirs. Both have marinas. Both are good fishing lakes, Casitas being world class for large mouth bass. Casitas takes reservations, Cachuma is first come first served but if you get there on or between Monday and Thursday, you should have no problems with a full hookup.