I work for Trulia and live in the Sleepy Hollow area of San Anselmo. To me it feels like a small town. Although its only 45 mins from San Francisco, it has a very "country" feel. You are definitely surrounded by nature and its not uncommon to see deer or turkeys strolling through your yard. At night, since there is very little background light, you can see the stars very clearly. Often you can hear owls and coyotes.
The schools are awesome and the people/community is very kid friendly. You can see more info Trulia has on this area here: http://www.trulia.com/real_estate/94960-San_Anselmo/