Depending on your departure time and amount of luggage, you could take the KX Samtrans bus that takes the freeway part of the way. As with the BART/Caltrain option, it's about a 1:15 hr trip. The advantage is that there are more frequent departures during midday compared to Caltrain and there are no connections required. On the other hand, it's less comfortable and not an available option if you have more than a carry-on.

SamTrans policy: "If a passenger can carry the item(s) on his/her lap or store it under or next to him/her on a seat unneeded and not hurt anyone else, and not interfere with others, the item is probably safe to transport." The final decision will be made by the bus operator.