Thanks, I can buy in advance so that will help.

I had thought about the Emeryville option, but although I'm no stranger to BART, I am a novice at public transportation in the City and so wasn't sure how a) to use BART from SFO to whatever stop it would be to get the Amtrak bus somewhere in downtown, b) don't know what that stop would/should be and how to get to it from the nearest BART station, c) it adds a leg into an already convoluted trip (BART from SFO ----> Amtrak at Richmond to Martinez ---> Amtrak bus Martinez to Santa Rosa.)

Any further thoughts or suggestions very appreciated!