Hi, my daughter went to Columbine Montessori. It will probably be exactly your 20 minute drive (but it's all freeway, as they say!). I live in HR also but drove there. It's just off of C470 at Wadsworth and Chatfield (technically Littleton). It's in a building next to a church, and I never would have thought much of it unless I hadn't been urged by a friend to tour there. The teachers have been there forever (most of them 15 plus years) and are SO kind. Really, really liked it. Good luck in your search!