Marin is over an hour away by bus from SF, with no train or BART. Basically to work in Marin you have to live in Marin, so any company that moved there wouldn't be taking advantage of the SF/South Bay labor market. You're looking at closer to three hours depending on where you're coming from. There is a ferry from Larkspur but transit connectivity and parking are limited. The Tiburon and Sausalito ferries are worse.
