There are a ton of stangers in CO. Every year in the summer they have the Rocky Mountain Mustang Roundup (RMMR) in Steamboat Springs. MM&FF comes out sometimes even. If you want to contact a local club in Denver you can go to www.coloradostangs.com
They have a forum there. I used to be a member there, but am not anymore. Good luck. I love it here in CO. The only thing that sucks about being in CO is the elevation and how it effects your car's performance. I ran a 13.11 at sea level and only 13.95 here. If you have forced induction the difference is not as bad as NA, but expect to lose about 1 second in ET when you come out here if NA.