My rule with mountain biking is be sure to always hire the best bike possible, make sure its so good all you need to do is hold on and it will do the downhill work for you. – that way you can focus on getting to the peak. located just outside of San Fransisco is trails to the Mt Tamalpais peak. With no shuttle buses currently operating you’re going to need to get on the 140km+ loop track via Muir Woods and the coastal track.