George and Judi,
Colorado - we did the Pikes Peak Cog Railway and Air Force Academy - enjoyed both very much.
Mesa Verde is one of our favorite National Parks - make sure you take the ranger guided tour (1/2 off with your America the Beautiful Pass) - very interesting to be in the "ruins"
An hour away from Mesa Verde is the "FOUR CORNERS". Some folks say it is a tourist trap but we went anyway and spent three hours there talking to the local vendors. Some very interesting arrow heads being made. We bought one and had the maker sign it for us (very cool). Keep it displayed in our foyer at home.
Utah - Arches National Park - another of our favorites. Sign up for the Firey Furnace Tour - again 1/2 off with your pass but do it early online because it does fill up fast. Make sure you take the Ranger guided tour the private ones are 10 to 15 times as much. We paid $7.50 for it and others who took the private tour were paying $100 plus. It is a 3 hour tour that takes you into the Firey Furnace part of the park. Wear good shoes and take water. The ranger is very informative and gets you to climb into to some very neat spaces. Very educational as well. Not difficult knowing you both are in great shape!!!!
Get to Zion National Park and try to camp in the NP campground - very, very fun. Many nice hikes throughout the park.
Grand Canyon is also one of our favorites. We actually did a three day hike to the water falls. Stayed on the Supai reservations. Probably the best and most adventurous trip we ever did.
On our way out West one of the campground host talked us into joining Passport America. We did and were not sorry at all. Many nice Passport Parks out West and the most we ever paid was $15 dollars a night. If you want more info I'll send you a private email. We did not reserve any campgounds except for the NP ones. Others we just found as we were driving or did some rustic camping. Many BLM camps in the area.