Originally Posted by skidder

That changes everything. While there are a lot of farm roads in the Salinas Valley, I have no clue how you'd get there from Santa Monica (Santa Monica Mtns fire roads, maybe the Los Padres Mtns have a good network, too?), nor what you'd do once you got near San Francisco area (Santa Cruz Mountains & other coastal ranges).

Idea: for info on possible northern Calif MTB routes try posting a thread in the Northern California forum. Someone there might be familiar with routes in the local hills in that area. Overall I think you're going to have to use a lot of asphalt roads to get there from here.