You can actually turn left after getting all the way down from Conzelman road. Right gets you back – either up Conzelman, or through the tunnel back to the bridge.
This time I went for left and ended up on Rodeo Beach. It was an interesting mix of surfers, families and mountain bikers trying to conquer the hills heading towards Mt. Tam. I didn’t stay for long, but it made me curious.
Back I then found out that the little road that branches off Highway 1 at the end of the Bolinas lagoon actually leads all the way up to Alpine lake. That would have been quite the shortcut, if I had known about it!