There may still be a club out in Golden at the railroad museum (https://www.denverhomodelrrclub.org/ ). There was an N-Scale club in the Forney Museum, but I'm not sure they're still active.
The NMRA does have a South Suburban division that meets in Littleton (http://www.sosuburbandiv.com/ ), although I don't think they meet around a layout. Attending one of their meetings might net a club.
Additionally, when I go to the local shows there are some clubs there, not sure their locations in and around Denver-metro.
Much obliged! IIRC, yes, there is a club at the Colorado Railroad Museum. It's a bit far for me to go, but the South Suburban division sounds interesting. I'll check with them. Thanks, again!