Agree with Thom on the time you will need to see and drive between all the places you list. I have lived in Colorado most of my life and been to all those places multiple times. Keep in mind that Denver to Durango alone is a 7-hour drive while towing our trailer via US 285 and US 160, which includes climbing nearly 11,000-foot Wolf Creek Pass. Mountain roads in Colorado during summer peak season are NOT fast, especially for RVs.
I would also second camping at Ridgway State Park, where we just stayed in October (one of our favorite CO state parks). All of the FHU sites are located below the dam. We always stay on the hill above the lake at electric-only Elk Ridge. The views of the San Juans from Ridgway are second only to those in Tellurde, which is on that road from Mesa Verde to Ridgway via Lizard Head Pass that Thom suggested.
If you have trouble getting Mesa Verde reservations at Morefield, take a look at the USFS McPhee Reservoir Recreation Complex. It's only 10 miles from the new MV visitors center and next door to the Anasazi Heritage Center. The AHC has interactive exhibits that will teach the kids more about Ancestral Pueblo life than any museum at MV. And it has two small excavated pueblos right behind the museum to explore. Definitely worth a couple of hours before heading for MV.
No matter where you decide to go, you will create some lasting Colorado memories!