Two cautions re: Caltrain if that is what you end up deciding:
1. There are two versions of the free VTA #10 bus. One goes to Caltrain (Santa Clara), the other goes to light rail (I think signed as Metro or something like that). Make sure you get on the right one.
2. There are two types of Caltrain cars. On one type you board roughly at platform level and would be fairly easy to get large/heavy/awkward luggage into. Unfortunately this type has no luggage racks. The second type *does* have a luggage rack (usually in one of the middle cars of the train), but also has 4-5 steps from platform level into the car.
I would also form a backup plan, because depending on when you arrive and on what day of the week it could be 1.5 hrs between trains (if the current weekend schedule holds; I forget exactly why they reduced the frequency or if/when that is supposed to end and return to hourly)
Schedules