Start/End: We ran out and back, starting and finishing at the Novato Sports Basement.
Notes: There is no official trail from Novato to the Petaluma River and Black Point, and the proposed Bay Trail runs along Hwy 37, which is a freeway, through this section.
As a result we took the SMART train line path north to downtown Novato, then roads across to the river. The highlight was a farm with chickens and baby goats.
One alternative possibility, though kind of sketch, is to travel along the railway line. This seems like it can be accessed just south of Hwy 37. The Bay Trail crosses it. We've heard it might still be a live line, a few times a week, and in the future it might be part of the SMART railway, so if you do this be very careful and you don't hear it from me.
Anyway, the Bay Trail is a work in progress, and some road running around gaps is part of the fun.