I fly with the Northern Colorado Rocketry Club primarily and with Tripoli Colorado. NCR flys in the beautiful Pawnee Grasslands with a standing waiver to 20,000 feet AGL. It's a fabulous area with two launch sites, the Atlas and the North Site. Atlas is for winter use with a waver of 12,000 feet AGL. Tripoli Colorado flys at Hartsel and offers extreme views and bison too. (Bison fencing is not easily crossed).
Both clubs have incredibly friendly and knowledgeable members. Highly recommended.
I'm a BAR having a blast figuring things out. I've crashed, lost, and damaged a significant number of rockets, but still love doing it.