L.K.
I also live in Thornton, and there is a great preschool that used to be called Wonderworld, Inc. (I'm not sure what their new name is) 1540 Eppinger Blvd. Thornton, CO 80229. Phone: ###-###-####
My 7yr old daughter attends Highland Montessori in Thornton. This is its first year of operation and it is part of the public school district. My daughter loves it, is doing so much better in school this year, and I REALLY like her teacher.
http://www.mapleton.us/