i plan to stay all 4 nights in SF. i am not going too far, must be a day to Standford or UC Berkeley, or a day to Monterey. i don't want to change hotel for the 4 nights. i am thinking of stay in downtown and rent a car for 2 or 4 days, or stay away from downtown and rent the car for 4 days. based on that, what are the choices of the area? thanks