It would seem to me to make some sense to extend the line at least to Tamalpais Drive. There is a buildable area right off Tamalpais and Redwood Highway, just off an interchange with 101 and across the street from a large shopping mall. This could be the main southern terminal with storage tracks and transit connections, plus some additional commercial or residential development.

In fact, forget trying to tie in to the Larkspur Ferry Terminal (the walk across Sir Francis Drake and the parking lot from where they plan to put the station now I am certain will turn a lot of people off) and build a new ferry terminal as additional capacity right near the terminal at Tamalpais. You could have a more direct connection and add capacity (both boat and parking, which the Larkspur terminal sorely needs).