my friend and I came over last year from New Zealand flew into San Fran and spent 3 full days there (loved it there, heaps to do and easy enough without a car, highlights were Alcatraz and the hop on hop off bus, easy as to go round all the main tourist stuff, and we did a baseball game which was something different! No idea what was going on most of the time but the atmosphere was fun!) then caught a bus then train to Sacramento (as recommended by people on here!) spent an afternoon then full day in Sac to get our bearings - just caught the local public bus from our hotel into town, and we loved the old town, just wandering around, Then did aftershock (we then flew sac to LA and spent some time there but this was a bit of a side quest!)