One thing to consider, other than the traffic issues through SF on 101 is the toll to get into SF from the Golden Gate Bridge: it's currently $31 for a 4 axle vehicle, and there are NO toll collectors on the bridge - they take a photo of your license plate, then track you to your home address and send you a bill. If you miss receiving that bill then they start adding penalties to the bill.
If you head east over the Richmond/San Rafael bridge you don't pay a toll, and you can then drive down the east bay on I880 into San Jose - but you still deal with traffic.