The typical asking rate per listing is in the $20's per square foot per year. The Doylestown region is going through a a boost in rates. In the last 3 months, the median rate increased $22 per sqft per year.
In the last 90 days, 11 listings have been posted online, which means spaces are probably going fast. You'll want to be prepared to make an offer immediately. About 27% of the listings in the Doylestown are subleases, so you might be able to find a shorter term or below market rent. 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 1,700 sqft. Most buildings in this area are close to 2 floors. Most buildings in this region were built in 1900 and are Class C.