This is one of my favorite rides, though it has been a while since I lived in the Bay Area. I did this multiple times and would make a three day ride and take the train back (first day to Monterrey, second day to San Simeon and half day to SLO to catch the afternoon train). I was using motels as often as camping, so if camping that gap from Monterrey south can be long to San Simeon.

The general idea was to cross over to Santa Cruz, going by way of Los Gatos bike trail and Old La Honda road. After mostly back roads to Monterrey and then mostly US 1 to San Simeon and then back onto some back roads into SLO.

This link from Caltrans: http://www.dot.ca.gov/dist05/bike_ped/bikeguide/bikeguide.pdf gives some of the better routes and this link: http://www.terrymorse.com/ also looks like it has a bunch of good information and maps. Adventure Cycling and Bicycling the Pacific Coast (Spring and Kirkendall) both also include route from Santa Cruz southbound.