The Berryessa station, at least, should be bikable from a decently-sized residential area, not to mention reachable by light rail or bus. We'll see what people actually do.
When I lived far out in the suburbs there was a commuter train once an hour and I could always count on being able to drive the freeway faster, even in traffic even though it was miserable.
EDIT: Yeah, this is flippant, but far as I can tell it's the truth. Policymakers are well aware that public transit is often not the most attractive option, and are working to bring it to the top of your list of options by degrading driving until it's worse. Congestion pricing, parking scarcity, reducing road throughput, etc. I guess in principle some of this might make buses more attractive, but not trains.
Stuff like congestion pricing isn't intended to increase use of public transport (that's a side effect), it's intended to reduce traffic and make driving "better" (by pricing lower-income folks out of it, but that's generally how "better" works in the U.S. anyway).