Route 60/77 Between Show Low & Tucson, AZ

I drive it two or three times a year with my Pick up and FW. There are some very steep grades (8%+) and switchbacks in the Salt River Canyon. But the road is good. Just gear down on the down hills, and try to maintain your speed on the climbs. Allow traffic to pass when there is an opportunity, and you should be fine.

I've seen several fully loaded tractor/trailers use that route, and they make it. The only time I really sweat it is when it's 110 degrees out. But even then, the rig never seems to overheat.