Thanks everyone for suggestions. I'm now researching RV campsites near Los Angeles, in Los Angeles or near public transportation to L.A. Anyone have any suggestions? Any areas of L.A. to completely avoid - every city has them? We plan to stay 4/5 nights - so convenience, safety, cleanliness is what we require. Of course, we'll leave the trailer at the park and use our truck to get to L.A. or even better drive to public transportation.

I don't think you will find many campgrounds near Los Angeles. Land is too expensive. I did a very quick Google map search and the KOA in Pomona might be your best bet. What other sites did you find?

Also the place we stayed in Half Moon Bay was Pelican Point. One thing to know about it is that they insist on you arriving at a specific time and they guide you into your spot. So you have to arrange an arrival time. And it's true that some of the spots need it. The managers are kind of sticklers. At the same time, the park was clean and neat. Google map it. Really is by the ocean.

I looked through my LA camping bookmarks and Malibu Beach RV Park is the best of the lot. I’ve always wanted to stay at Crystal Cove State Park too.

i generally really like California state parks and I would echo that I’d focus on nature. Save SF for another time. Maybe focus on Southern California and/or teven the Southwest this trip. But there’s seriously a lot of great nature in CA and I think I’d save the cities for when you fly into them.

Thanks I'm working my way up the coast with campsite reservations. Currently looking at the San Luis Obispo area for 3 nights. Then on to the Monterey/Big Sur area. And finally San Francisco. So I'll keep your recommendation in mind for SF.

Thanks we decided on Dockweiler RV Park, Playa del Rey for our LA base. We've decided another trip we'll do Yosemite, Sequoia, Redwoods when it's warmer - most likely September.

About 50 miles south of San Francisco, you might want to know about Ben Ries campground in Butano State Park. It is in a grove of huge Coast Redwoods. Nearby is the Pigeon Point lighthouse which also has a HI hostel.
On the ocean side of US 101 you also have Ano Nuevo Park.

Are you looking to camp on the Monterey Peninsula or Big Sur? The state parks around here don't have hookups so you'll need to look at private campgrounds in Big Sur. Near the peninsula, Laguna Seca has the least expensive sites with water and electricity and is about 15 minutes to Monterey/Carmel Monterey County, CA : Camping although unless you've changed your schedule, you'll be here right in the middle of Sea Otter Classic so there won't be availability then.

In the Carmel area I recommend Carmel River RV Park. Leave the trailer there and spend all day exploring. It's easy to drive into Big Sur and then go back to the park later that day or evening.

Morro Bay State Park has some sites with hookups. There are also some private RV parks near the rock. Do note that they are next to the wastewater treatment plant. I really like the state park the best. I would stay in just one place in the SLO area as it's really easy to get around. You can visit Pismo Beach, Avila Beach, SLO, Cayucos, Cambria and San Simeon easily if you base yourself in Morro Bay.

In the San Diego area, do go over to Coronado Island, and explore the northern 'burbs of LaJolla (notably LaJ Shores), DelMar, and especially Encinitas & Carlsbad where there are great RV beachfront spots (Ponto Beach for one in Carlsbad). Believe there are RV parks around Mission Bay, a good base from which to explore downtown SD.

South Carlsbad State Beach, Carlsbad

(Tent & RV Camping) This linear campground is on the bluff in North County about 30 minutes from downtown San Diego. With 223 camp spots South Carlsbad is your best best for getting space if you didn’t reserve one. The beach here is narrow and might be all wet in some places at high tide. At both ends of the campground there is more sand at North Ponto and South Ponto beaches.

San Elijo State Beach, Encinitas

(Tent & RV Camping) This large campground is on the bluff in the Cardiff area of Encinitas. It has 171 camp spots that are all just steps away from stairways leading to the beach. Just north of San Elijo State Beach is Swami’s a popular surf spot and to the south is Cardiff State Beach which has several excellent restaurants.

Campland on Mission Bay in San Diego

(Tent & RV Camping) Campland is a privately-owned campground on the northern shore of Mission Bay in San Diego. It’s great for families as the kids can play in the water without fear of big waves and rip currents. It also means there are more water-based activities for everyone to enjoy.

You might want to check these areas out as well.