New Castle is about 15 minutes West of Glenwood Springs, and it is a "bedroom community", meaning people commute from there to work. If you can live in Glenwood, there are many good jobs and no commute. Most of New Castle was formerly a large ranch, now with about 550 homes. Glenwood is in a narrow river canyon and there is not much room to expand. So by the rule of Supply and Demand, Glenwood has high demand, but little supply (not as many houses) and that makes each house more "valuable".