Other than RMNP, what can u do in Denver area?

My hubby John and I (I use a scooter to get around most of the time as I can’t walk long distances anymore due to various medical reasons) are coming to CO for 2 weeks starting 6/29/19. We’ll be renting a 30’ Class C and right after that we’ll need to have some camping facilities booked somewhere. The only thing my husband has said that he wants to do so far is; rent a car so that we can go into Denver proper to visit the State Mint, visit some type of Mexican town that he recalls from his childhood, visit the RMNP, he wants to do some hiking, mountain biking and who knows what else. We might meet up with one or 2 of his nephews for a few days of camping but that’s about it. My dilemma is that I always do the itinerary but for some reason, I don’t have a clue as to where to start etc... what I know for sure is that I have to return the RV the morning of July 13th. I also know that we’re coming at the worse time of the year to visit the Park and that if I had it my way, I would have gone in September but .... we’ve already been to Colorado Springs and its surroundings as well as Pikes Mountain and the train and also to the Royal Gorge then the Great Sand Dune Nat’l Park, Durango then Mesa Verde Nat’l Park. And Just last Spring we went from Denver s/b on 25 all the way through NM to I-10 W/B to Nogales ( slight detour) then N/B and N/W through Tucson, Phoenix, and so on. All that to say we’ve seen some of Colorado but there’s still a lot to see I know. We even went to Dr.Jeff, Rocky Mountain Vet’s Clinic but he wasn’t there... So where should we go during those 2 weeks other than where I said? Don’t worry about making sure that both of us can or want to do what you are suggesting as I usually need to sleep in the afternoon... I’m eager to read what you have to say.