This may not be the best route, but it's one way.
Take VTA's Route #970 express bus to Santa Cruz Metro Center (that's downtown, and the main transportation hub).
See www.caltrain.com for schedules.
You can navigate to it independently, but here's a list of stops for #970 I have handy:
I don't know how long this will take, but I think you can figure it out from these two sites.