On average, listings lease in the $30's per square foot per year. The Lucas Valley-Marinwood submarket is going through a a boost in rates. In the last 3 months, the median rate increased $36 per sqft per year.
Compared to the rest of the Bay Area market, the Lucas Valley-Marinwood region has less expensive rates, so you should have no trouble finding a great deal in this undervalued submarket.
In the last 90 days, 7 listings have been listed, which means new listings most likley are going fast. You'll want to be prepared to make an offer immediately. About 43% of the available leases in the Lucas Valley-Marinwood 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 posted, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 240 sqft. Most buildings in this market were built in 1980 and are Class A.