We found the best way to enjoy our trips was to decline in making many reservations ahead as this locks you into "needing" to arrive at so and so place by so and so date.
If you see a town or a sign advertising something, or a historical marker, you would like to check out, do it!!! Don't say, " we'll check it out next time ", because more than likely you'll never get back to it. Some of the best places are off the beaten path.
While in Tennessee, go to Smoky Mtn. Knife Works in Sevierville, TN, really awesome place, your wife should love the lower floor with all the 'kitchen' stuff, etc.
If you visit Utah, go to Arches National Park and the Devil's Garden Campground.
In Oklahoma in the pan-handle, check out the museum at Boise City, OK. Small town, very interesting museum and local history, schedule the time to visit the Autograph Rock and a tour of the old Fort in the area. There are also dinosaur digs in the area.
In the Four Corners area, there is an tour that is operated by the local Native Americans and they take you on a tour of their lands where there are dinosaur footprints.
New Mexico has a plethora of 'old west' history to explore. Old missions, ghost towns, awesome museum at the El Camino Real.
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Enjoy your travels, see the backroads, and stay safe.