In the last 90 days, 2 listings have been listed, which means spaces most likley are leasing quickly. You'll want to be prepared to make an offer immediately. About 50% of the available leases in the Tarrytown 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 posted, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 2,500 sqft. Most buildings in this region are close to 6 stories. Most buildings in this area were built in 1965 and are Class A.