Allrighty then, two routes to choose from.
Mount Tam - Mill Valley - 37 miles and according to MP about 3,000 feet of climbing. I have not ridden the Mill Valley section of this route.
Mount Tam - Muir Woods - Olema - 73 miles and 6300 feet of climbing. I did this ride on 7/26 and then a bit different configuration on the Mount Tam double. It's a beautiful ride, goes up the coast. Rte. 1 is a bit rough in the beginning, a good climb and then some rough ride. But so beautiful since you're right on the water.
V.