I haven't been to the area recently so I can't vouch for their current standards, but these were my two two faves in the area:
The first is The Buckeye in Mill Valley. Only in Marin County would this be called a "roadhouse."
A bit fancier is the Lark Creek Inn in Larkspur near Corte Madera.
Both are easily accessible from 101.
www.buckeyeroadhouse.com www.larkcreek.com