any interests?
http://www.bikely.com/maps/bike-path/SF-Caltrain-to-Mt-Tam-to-BARTThere are a few options on where to start, but that's about what the ride will look like.
edit:
let's talk about start time. First sat trin gets to SF around 8:40.
There will be 3 different meet up spots.
9am at my place. by the SF zoo, 46th ave and Vicente.
9:30-9:40 at Cafe on Arguello and McAllister
10:00 - 10:15 at GG bridge visitor center. Where the bathrooms are. this is your option if you are taking the train.
Let me know if you are coming and I'll give you my cell#.