If your in Denver for a couple days make it easy on yourself and hang out in LoDo. There are tons of places to eat and hang out depending on your mood and interest. This area is from around Coors Field to a few blocks SW of 16th Street mall. Jax Oyster Bar is great. Bunch of places in Union Station. Larimer Square. Beer gardens. Shopping. Comedy Works. Howl at the Moon. ViewHouse. Denver Chop House. For mex food Illegal Pete’s is cool. And it’s all surrounded by conv center, Pepsi center, aquarium, elitch, museums, etc.
Boulder has got Pearl St but it’s a bit touristy. Cool hiking trails all around. CU campus. People go tubing in the canyon but the waters too cold for me in springs.
Estes Park is a great place to chill out. Lots of shops downtown. RMNC trails. The Stanley Hotel (The Shining) is cool for dining.