The Rocky Mountain Treehouse is located in the town of Carbondale, which is located between Glenwood Springs and Aspen. It's described on Airbnb as a treehouse that was built in 1971 and sits on two acres. It also has a large balcony and hot tub, which could make your experience more enjoyable. The treehouse can sleep up to six guests and is around $220/night on average.
The Little Red Treehouse will probably be the closest drive for you as it's situated in the town of Lyons. It's described as having huge views, decktop private shower, along with having heat and electricity. The treehouse can sleep up to three guests with one pull down bed and a loft for one person/child. The cost of the treehouse is $250/night on average.
The Treehouse at Highland Haven is located in Evergreen and costs an average of $550/night. It's described as being 850 square feet and has three levels to it. It has a stone fireplace, two person steam shower, and a "champagne bubble" jacuzzi. It's also walking distance to downtown Evergreen.