If you are really looking to experience the Colorado Rockies take a trip out to Silverthorne. A little over an hour outside of Denver you can experience breathtaking views and beautiful mountain ski towns all within minutes of one another.
Keystone Resort - https://www.keystoneresort.com
Breckenridge Resort - https://www.breckenridge.com
Frisco, CO. - https://www.townoffrisco.com/
An incredible city with great things to experience. Kristen and I have had the opportunity to explore this city quite frequently and we have a few suggestions.
Check out Larimer Square off of 16th street.
The 16th street mall is a great place to walk around and check out what the city has to offer.
Obviously Denver sports centers are a must see. The Pepsi Center, Mile High Stadium and Coors Field are with in 15 minutes walking distance of each other close to 16th street mall.
Additionally, there are various Museums and the Denver Zoo
If you are not renting a car, we highly suggest using lyft/uber. Or, for a cheaper and more adventurous option, renting the electronic scooters and bikes to travel around the city.
This is a really cute little town nestled right on the front range. A great place for hiking, or just to walk around, buy a few souvenirs and catch a great meal.
Kristen is currently living and teaching here in this incredible town. It has all the elements of a small town with endless things to do. We will be moving here after our wedding and spending the next year or so in this town. It is about an hour north of Denver but worth the drive if you have a few spare hours in the day. This is also on the way to Estes Park if you choose to go hiking there!
Check out Old Town and the Shops.
Anywhere in Estes Park/Rocky Mountain National Park (Moderate to Difficult) *worth the drive*

Royal Arch - Boulder (Difficult)

Barr Trail to Pikes Peak - Manitou Springs (Difficult)
Garden of the Gods Park - Colorado Springs (Easy)

Coors Brewery