personally, i would try to get a rental car (check hotwire, aaa.com/hertz, hertz's 14.99 prepaid weekend special http://www.hertz.com/rentacar/q-13480376/prepay-and-save-$14-99-weekend-special-special-offer).
you can get around via public transport. at SJC there is a free city bus (
http://vta.org/schedules/SC_10.html) that links SJC with the santa clara caltrain station, as well as the VTA light rail system.