You can ride the Bart from SFO or OAK to the Embarcadero area and get a cab from there. You could also take a shuttle for around $20 per person. Parking in San francisco is just out of control. Last time I was there I paid $40 per night. I don't think you will have a problem finding a rental can in the area. Most major hotels have desks in their lobbys. You might also want to see the Golden Gate Bridge. The tour of Alcatraz is also a great fun thing to see, and it does not cost that much. If you go make sure you get the audio tour. Also buy the tickets online early before you go as June is high season and you won't get tickets at the window, trust me on this one. http://www.bart.gov/index.aspx