On average, listings lease in the $10's per square foot per year. The Dover region is going through a decline in rates. In the last 3 months, the median rate fell $5 per sqft per year. That's a 20% decline in rent.
Compared to the rest of the Greater Boston market, the Dover region has smaller rates, so you should have no trouble finding a great deal in this undervalued submarket.
In the last 90 days, 44 listings have been posted online, so you'll want to check back regularly for new listings. About 50% of the available leases in the Dover are subleases, so you might be able to snag a great spot on a short term. 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 2,000 sqft. Most buildings in this market are around 2 stories. Most buildings in this area were built in 1950 and are Class B.