In the last 90 days, 4 listings have been made available, which means leases most likley are leasing quickly. You'll want to be prepared to tour spaces as quick as possible. About 25% of the available space in the Riverside 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 1,400 sqft. Most buildings in this market are approximately 2 stories. Most buildings in this region were built in 1990 and are Class A.