We've visited Rocky Mountain National Park several times and it's got hikes for all levels. The main entrance is only about 1.5 miles from the venue. This summer they will require reservations for the main entrance and those will open 30 days prior to the day you plan to attend. The main picture on our website, is us there in November 2019, and here's another shot of us there in September 2016.
If you like The Shining, visit the legendary hotel. You can drive by to see or they even have some historical tours! https://www.stanleyhotel.com/tours.html
Want the views without all the sweat? Assuming they re-open this season, this is a great way to see Estes Park from up high.