David,
We have made a couple of trips to Colorado and one trip to Utah and Arizona in the past. I would suggest that you pick one or the other, not both for a three week trip. If I wanted to see some of the parks in Utah, I would drive through Colorado on I70. You will get to see the Eisenhower tunnel and Glenwood Canyon from the highway. That is about all you will have time to see.
We found that when we got to Arches National Park the road into the park was too steep for me in my 28’ class A motorhome. At the time I was not used to mountain driving. What I would do today is either tow my Jeep or rent one in Moab, Utah. The KOA we stayed at rented them but I am sure others do also. There are so many parks that it is hard to pick just a few but the ones that seem to be the most popular are, Arches, Bryce, Zion and Canyonlands. We did not see many of the parks in Utah on our trip as we wanted to go to Arizona and the Grand Canyon. On the way south, we stopped at the Four Corners for about half an hour. Kind of neat to stand in four states at one time. We did have to take the picture of me standing in two states leaning over and kissing my wife while she stood in two other states, corny, huh. Mostly there where Indians selling stuff like T-shirts, art work, rugs and beads etc. There is a small canyon there also. We saw several arches just off the road from Moab to Four Corners.
We went on down to the Grand Canyon, went in at the east entrance, stopped at several parking lots to look into the canyon. I had a lot of problems finding a place to park the motorhome and the few I did find were on hills. I was not comfortable leaving the motorhome on such a steep incline, so my wife went to the canyon and took some pictures for me to see later. We went to the canyon village and had to park across the street, fight the traffic to walk across to the canyon and visitors center. Some people really like the canyon and others think it is just a big hole in the ground. I am of the later group. Maybe if spent a whole day or two watching the rocks change color as the sun moves across the sky it would be better. After leaving the canyon we went south toward Williams and spent the night at a campground called Black Bart’s. Black Bart’s is a restaurant where the wait help (collage kids) also sings and performs. We enjoyed the evening there.
http://www.blackbartssteakhouse.com/rv.html. The next day we drove forever to get to Tombstone and the OK Coral. The long drive made us appreciate what it took for the early folks riding horses and wagons to get to Tombstone. It was a very hot and dry day in May that we spend there. We missed to gun fight and the Coral is really small. I had to wonder how anyone could miss a shooting a man when they are that close. I don’t think the drive was worth the town.
I am a tree person that likes the green in the landscape. The southwest is not my cup of tea. That being said, someday we may go back to see some more of it. The picture Ron posted looks kind of interesting, so maybe there is more to it than we saw that I might like. That is the really great thing about this country, there is something for everyone to see and do.
Tom