Route recommendation: Arkansas to Alberta
You will certainly enjoy your ride from Arkansas to Alberta, especially the scenic route you outline via NM, AZ, and UT. I have some experience in the state north of Utah, namely Idaho.
In June 2006, I rode US Highway 93 from Arco ID north to Missoula MT, and it was a totally delightful ride, especially from Challis ID to Salmon ID. Between the mountains to your left and the mountains to your right are the busy Salmon River and the highway, and the traffic is probably minimal. If you leave I-15 just north of Pocatello ID, you can catch US26 then US20 to Arco, which I did. There's a nice rest area about half way from I-15 to Arco, but I don't recall its exact location. If you stop there and read the posters, you will wonder why the whole area isn't glowing.
North of Salmon ID, you lose the river but gain some lovely mountains. It's a good idea to get fuel at Salmon. Hamilton MT is a pleasant little town for a break or a motel.
I can't testify concerning the rest of your route, but I understand that US89 is a beautiful highway.
I tented overnight at rest areas on Interstate highways in IL, NE, CO, and ND, and only once was a broom pusher annoyed by sight of my tent. I expect to do the same this summer in VT, ME, NS, and PQ; if I survive, I will report here on my experiences.
Riddle me this: what commercial venture is earning money in Arkansas and Alberta but in no other state or province?
Answer: diamond mining! Diamonds have been mined in AR for about a century, and Grizzly Diamonds is apparently finding jewels in Alberta!