Common starts are either in Fairfax, or in Corte Madera just west of the park.
From Corte Madera go through Larkspur to Ross, then along Shady Lane to San Anselmo, and follow the bike route to Fairfax.
In the center of Fairfax take a left up Bolinas-Fairfax road, climb past the golf course, and keep climbing. A good regroup is the parking lot at the top of Azalea Hill, where the fire road to Pine Mountain cuts off to the right.
From this point descend (mostly) to Alpine Lake, and then across the dam. Careful on the descent, even early in the morning there are cars coming the other way. The dam makes another good regroup point.
From the dam, continue climbing along Bolinas-Fairfax Road, through switchback after switchback, to the gate at West Ridgecrest Blvd on your left.
I've never counted 'em, but many people refer to the hills along West Ridgecrest, as you're treated to beautiful views out over the Pacific ocean on your right, as the "7 Sisters".
Regroup at the big parking lot with the road to the top of Mount Tam. Pit toilets to your left. East Ridgecrest Blvd goes left to the top, Pan Toll road goes left.
At this point some folks do an up and back to the top of Tam, and often retrace the route to Fairfax.
Others continue down the hill, merging into the eastbound traffic on Panoramic Highway at the Pan Toll parking lot.
A left, almost doubling-back on to Sequoia Valley Road, which turns in to Edgewood Avenue, which turns into Molino Avenue, which, after a sharp left and turning into Montford Avenue, has a stop sign at Miller Avenue. Continue through the stop sign on to La Goma, take a right on Sycamore, and a left on Amicita to East Blithedale Avenue, where you take a right.
Almost immediately you'll take a left at the traffic light on to Camino Alto, which will take you back over the hill to Corte Madera.