Compared to the rest of the Bay Area market, the Sonoma submarket has greater rates, and you'll have to negotiate above asking rent to be in this hot region.
In the last 90 days, 16 listings have come on the market, which means leases 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 posted, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 830 sqft. Most properties in this area are close to 2 floors. Most buildings in this region were built in 1974 and are Class C.