Yiding and Jennie got engaged here! Timed-entry reservation is required to enter RMNP in September at Recreation.gov. Fall color is popping around this time of the year. There are many options for a day trip: consider a short hike at the Bear Lake corridor or drive through the scenic Trail Ridge Road. On your way there to/from Denver, make sure to stop by the Colorado Cherry Company (12311 N St Vrain Dr, Lyons, CO) for some delicious fruit pies!
For a Colorado fall season signature day-long road trip, the Maroon Bells is like no other. A popular route to enjoy the Rockies scenery is: Denver - Aspen (Maroon Bells) - Independence Pass - Twin Lakes - back to Denver. We would recommend leaving super early on Saturday morning. The parking permits (releasing on 6/17) at Maroon Bells will start selling out super quick and shuttle tickets will sell out fast as well. Day-of stand by shuttle tickets will be available but not guranteed.
Also a one-day trip option if you would like to summit a 14er: Pikes Peak is a great destination if you are not up for an 8hr hike because it has the world’s highest cog railroad, the Broadmoor Manitou and Pikes Peak Cog Railway, to take you all the way to the top of 14,115ft. Make sure to book your ticket in advance as it is a very popular destination this time of the year, driving is another option for flexibility of your itinerary. Also in the Colorado Springs area, stop by and drive around the Garden of the Gods, home to a plethora of geological and ecological rarities that make the park a prime site for nature lovers.
Serious question, are there other music venues that are considered more beautiful than the Red Rocks Amphitheater? It is close to town and perfect for your itinerary if you only have half of a day to spare. Noted that the venue is free to visit during the day and will be cleared for events by 5pm if a concert is scheduled that day.