This is a beautiful, family friendly ride with low traffic that ends at a beach! The route as outlined starts in Sausalito and meets up with the Sausalito-Mill Valley bike path, but it can be accessed coming North from Mill Valley and beyond.
Riding North from Sausalito, you'll travel on side streets and bike paths through Tam Junction. It's flat and easy cycling with views of Richardson bay and Mount Tam. After Tam Junction you will be traveling on a two way road with cars and a slight elevation gain. Our 5 year-old was towed along via the awesome TowWhee (sold at The New Wheel!). Since the road is narrow, this route is best traveled with a confident young cyclist and/or two adults - one in front and one directing from behind.
Once you arrive at Tennessee Valley trailhead it is car-free riding all the way to the beach! You can pack a picnic or return back to Tam Junction for delicious food at Shoreline Coffee Shop, The Junction Beer Garden / Pizzahacker (this was our choice on this trip and great place to visit with or without kids) or Hook Fish.