I used to live in Flagstaff. If you can hike Whitney in a day you can hike humpreys in an afternoon, it would be a 3-4 on the Whitney is 10 scale. It is around 9 miles RT starting around 9k. No water on the trail, zero exposure, maybe some deer and elk. The big risk is weather, if you are up there in the summer, the last mile and a half or so is above the tree line and extremely exposed to thunderstorms, so start early.
