In the last 90 days, 1 listings have been posted online, which means new availabilities most likley are leasing quickly. You'll want to be prepared to make an offer immediately. About 100% of the available leases in the Upper Saddle River are subleases, so you might be able to sign a shorter term by taking over a previous lease. 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 800 sqft. Most properties in this area are around 3 stories. Most buildings in this market were built in 1986 and are Class B.