Compared to the rest of the Bay Area market, the Larkspur submarket has higher rates, and you'll have to negotiate above asking rent to be in this hot region.
In the last 90 days, 6 listings have been made available, which means office spaces most likley are leasing quickly. You'll want to be prepared to make an offer immediately. About 100% of the office spaces in the Larkspur are subleases, so you might be able to sign a shorter term by taking over a previous lease. There aren't many listings below 2,000 square feet available, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,850 sqft. Most properties in this region are around 2 stories. Most buildings in this area were built in 1980 and are Class B.