Just three miles south of Half Moon Bay is Bob's Car Wash...one of those do it yourself car washes with power washers. They also have soapy brushes, vaccuums, for the inside, etc. Bring plenty of quarters, or you can also use their change machines...open 24 hours a day. They tell us they're used to big RVs who park outside, wash one side, then go around the car wash and wash the other side. It appears that most travel trailers will be able to make the turns out of the car wash as well. It's easy to get there..just go south on 1, turn left on Main and right after you cross highway 92, Bob's is on the right...
Here's a video showing it to you...