I've lived in Colorado since 1980. The first 31 years we lived and worked in Estes Park. So, Rocky Mountain National Park was out our back door. RMNP is a beautiful, beautiful place. However, it has become so congested that it took the fun out of living there. Since you are not hikers, you will be in the thick of it. Bear Lake has become gridlocked. You have to be there by 7:30-8:00 am to get a parking space. Otherwise you ride the shuttle buses which are efficient and timely. We were there this past summer for 10 days. Campgrounds are overpriced like everything else.
After retiring in 2010, we moved to Buena Vista, Colorado. It reminds us of Estes Park in bygone days. Lots to see and do and not overcrowded. Nice campgrounds and spectacular scenery. Don't miss Leadville north of Buena Vista. Sort of a summer tourist trap. But it is worth walking the downtown area. Black Canyon of the Gunnison is certainly worth the visit. Durango is busy and crowded in the summer, but the Durango and Silverton Railroad trip is spectacular. The Cumbres and Toltec Railroad in of Antonito or Chama is fun. The Ouray area is busy in the summer but has beautiful scenery.