If you go the route Dallas-OKC-Denver, Cheyenne-Pocatello it's probably quicker but the scenery is not as good IMO. When we go to MOab & SLC we always stop in Austin, TX to spend some time with grandkids. So, from Dallas area take US287 to Amarillo, I 40 to Albuquerque then 550 to Farmington, NM to Bluff, UT. Then stay on 191 thru Moab and continue to pick up I70 at Crescent Junction, West to US6 to I 15 thru SLC and on to Pocatello. The later route will definitely be more scenic and you'll burn more fuel due to mountains. The latter route has some 2 lane in it too.......good, wide 2 lane but 2 lane none the less.
We'll be heading to Moab via Austin the later part of April. Have a great and fun trip.
'02 Ultimate Advantage 40J Spartan MM - Cummins ISC
2013 Jeep Rubicon JK Unlimited