Any personal recommendations on where to hire a camper van in or near San Francisco?
It may be worth checking out AirBnB as they do reasonably good deals on a variety of different user-owned motorhomes.
Jucy vans rent out of oakland (close to BART) and they are super affordable and easy to use. I have rented from them in the United States and New Zealand 4 times and I have had s fantastic experience everyone. Keep an eye on on their twitter as they do run promotions & 1-way deals.