One of our favorites is Doran Regional Park. It's a Sonoma county campground. The park is situated on a large swath of land between Bodega Bay/Harbor. It's easy to get to from Petaluma off Hwy1. The bay and harbor are beautiful with a view of the Tides wharf,where the Hitchcock movie The Birds was filmed. There is a large,long beach area for walking,relaxing,fishing and easy drive to Bodega Head for whale watching.There is water but no electric or sewer. There is a dump station in the park. It's a popular park so reservations are recommended but they do have first come first served. It's also a great place for birders. The white pelicans are huge and beautiful and fun to watch as they work in tandem to catch fish.
Dec and Jan are great months. We spend every other Christmas there. The weather can be warm and sunny or windy and rain. We love both. You can usually have your pick of campsites in December.