Wardog, I'm not sure of your route to Prescott & I-40, however if you take I-17 north out of Phoenix to Prescott and Flagstaff, you will have some good pulls & hot weather. Phoenix is about 1100 ft in elevation, with Flag at 7,000. I-40 east to Albuquerque is mostly just rolling hills nothing big or steep, but takes a good amount of fuel as you travel up and down in elevation. I-40 has heavy truck traffic both ways. I-25 north of Albuqueque to Denver is also easy going, except for the pull out of Raton, NM. It is a good 6-percent up and down. The traffic is cut in half untill you get to Denver, then gets crazy, lots of road constuction, always. With your rig you will be fine.
"NICK"