Compared to the rest of the Bay Area market, the Tamalpais-Homestead Valley region has more expensive rates, and you'll need to make a great offer to be in this hot submarket.
In the last 90 days, 2 listings have been posted online, which means new availabilities most likley are leasing quickly. You'll want to be prepared to make an offer immediately. There aren't many listings below 2,000 square feet posted, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,270 sqft.