@MHowell I stayed at the top of the canyon, mostly, but did take several hikes along the rim and one day took a trail partway (but not all the way) down to the bottom. I'm told that the Tarahumara natives, many of whom live at or near the bottom, regularly climb all the way to the top to sell their hand-woven baskets and other wares. Their endurance at walking (and running) is legendary.
Oh, I also rode a long zip-line across part of the canyon -- wow, what an exhilarating thrill! -- then had to take a steep hike up to board an aerial tram back to my starting point. That was an awesome day.