If there was a trick to this week's Mystery Photo, it was that the buildings were not authentic. Rather, this is the Western Town at Paramount Ranch in Santa Monica Mountains National Recreation Area.
Originally built by the Paramount Movie Studios, the Paramount Ranch Western Town is now owned and operated by the National Park Service. It is still an active filming location. It stood in for Colorado Springs in the TV show "Dr. Quinn Medicine Woman" between 1992-1997. The gray building was the good doctor's office in the series. It looked a bit different back then, but then it looks different today and will look different again tomorrow. As a movie set they constantly add new buildings and facades, even bringing in fake trees and other foliage.
The Western Town is open daily to the public (portions may be closed for filming, but you can watch the action) and admission is free. Much cheaper than the other big-name studios!
For more details on this spot, check out this site.