On average, listings lease in the $30's per square foot per year. The Lucas Valley-Marinwood submarket is going through a an increase 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 discounted region.
In the last 90 days, 7 listings have come on the market, which means office spaces are probably going fast. You'll want to be prepared to tour spaces as quick as possible. There aren't many listings below 2,000 square feet on the market, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 170 sqft. Most buildings in this market were built in 1980 and are Class A.