Compared to the rest of the Denver Metro market, the Castle Rock submarket has smaller rates, so you should have no trouble finding a great deal in this depreciated region.
In the last 90 days, 18 listings have been made available, which means spaces most likley are leasing quickly. You'll want to be prepared to make an offer immediately. About 11% of the office spaces in the Castle Rock 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 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 1,500 sqft. Most buildings in this region are approximately 2 stories. Most buildings in this area were built in 2001 and are Class B.