I really like that RV park in Tehachapi - we called once - we only had two nights, and I was hoping to stretch it out, so I asked if we could check in fairly early on the day we got there and leave about 4pm on the last day. They said that it would be fine, and they did not even charge us. That said, it was very empty (which I also loved). It was fun to watch the gliders take off.
There is a fabulous bakery in town, near the old RR station.
In Morro Bay - Morro Bay SP is very nice, but also one of the most popular RV parks around. If you are lucky you might get a hook up site. `If you have a smaller rig, and do not mind primitive - vault toilet, head abck to Morro Bay SP for showers, then consider Montana De Oro SP. It is in a lovely area.
Since you will be there in December, definitely head over to Pismo Beach SP and check out the butterfly grove. The last few years they have had about 30-35K butterflies in a small grove. It is definitely worth seeing. Also head up north beyond Cambria to see the Elephant Seals. There should be a nice light display in Cambria, too.