Might I suggest another route option for climbing Tamalpais?
Start in Stinson Beach. Ride north on Highway 1 along the Bolinas Lagoon for about 5 flat miles.
Turn right on Fairfax Bolinas Road and begin climbing from the grasslands up into the Redwoods on a narrow winding road with little traffic and some excellent views. The steepest sections are in the firs two miles.
After about 5 miles turn right on Ridgecrest Blvd. for 7 more miles of climbing to the top with some short descents thrown in for good measure. The views of the Pacific Ocean and the coastline below you are stunning. You've probably seen Ridgecrest Blvd. before in a car commercial.
You can then descend back to Stinson via the shorter Pan Toll Road and Panoramic Highway.
Yes, week days are best, but as long as you get an early start (before 9AM) on the Highway 1 portion the weekend traffic isn't bad on this route.
Have fun!
Brent