I backpacked the Canyon 50 years ago in the week between Christmas and New Years with a friend who was a geology major at UCSB. He's retired professor now. We lugged 50-odd pounds of winter gear and freeze-dried rations, with little Svea stoves; no fires allowed in the Canyon.
We started out on the Kaibab Plateau and hiked until we hit the Bright Angel Trail, and banged a left down to Phantom Ranch* on the other side of the river over that swinging bridge, where we celebrated New Year's Eve. I wore my sneakers like slippers all the way up Bright Angel to the South Rim, having burned my well-seasoned hiking boots. There were signs that told you that you could hire a mule to take you back to the top, but it would cost you beaucoup bucks. I walked.
We hit some hot springs in the middle of the night on the way back to Santa Barbara. Toughest backpacking I'd ever done, before or since.
* Interesting note: Everything at Phantom Ranch came down there by mule or burro, and later by helicopter. The big-ass Garland range in the little restaurant kitchen came down in the smallest pieces possible to be reassembled when the last mule got there.
I remember reading that they started mapping the Canyon in 1911, and they weren't done yet. Satellites may have hurried things along since '75, I don't know. But damn! your beautiful photography brought back some great memories! Thanks.