Look up the Mile High Dungeon. It's around the Lakewood part of Denver. Lots of fun equipment to be tied to! I can't recommend any mistresses there, however, since the only one I sessions with there doesn't travel to Denver anymore (she does just San Francisco now).
I THINK Mikayla Miles (the Mile High Domme) does sessions in Denver. If not, looks like she'll be visiting Manhattan near the end of September .