What area of Denver is your conference? I prefer the Denver Tech area or south of DTC near Centennial for hotels (quick access to I-25) and food. I can’t help ya with the indoor shooting range, but El Paso county (Colorado Springs) in conjunction with Fort Carson just opened a brand spankin new shooting range called Cheyenne Moutain Shooting complex. http://www.elpasoco.com/CMSC/Pages/default.aspx
I think only phase I is open/completed which is the outdoor ranges.
Probably next to airport or downtown if they follow most NRA courses.
LOL....just got a private mail that "Shotgun Willies" is a good place for drinks...rated best strip club in CO.