Beautiful shots!

Here are a couple.

I'd love to see the return of some Kodak films, but would you have to send the exposed rolls to Kodak to develop?

I was always told that you never want to put cheap glass (or plastic) in front of expensive glass. I never use any filter other than B+W or Hoya.

I love it! But then for Ansel Adams 35mm was a cropped frame.

A lot of good suggestions here. Another good instructional video can be found on Creativelive.com. It costs $19, but the "Nikon D7500 Fast Start" video with John Greengo is well worth it.

I have Kirk L brackets for both my D7500 and D810 and think they are great. I also have a Kirk ball head on my old Gitzo tripod and have never had a problem. The L brackets allow full access to the side panels and battery. I've toyed with the idea of an RRS ball head, but so far the Kirk works just fine.

I went for three weeks last summer to London, far northern Sweden and Iceland and carried a Nikon D7500 with a 18-105 3.5-5.6 DX lens and a 12-24 1.4 DX lens. The combo worked very well and was lighter weight than my full frame body and lenses. Although I rarely used the 12-24, I was glad I had it for the wider angle in some places. I carried the kit, along with raincoats and other daily outing necessities in a fairly small shoulder bag. We used primarily mass transit, busses, boats and the Underground and it worked very well.

ASA....

Why didn't you bring the feeders in at night if you live with bears? We do, and with Mountain Lions, Moose and others. And the camera is always ready. I haven't taken my rifle out of its case in years....

Won't be much of the Canyon itself until you get to the South Rim. Then its across the road and to the terrace on the other side of the Bright Angle Lodge or El Tovar.

Image stabilization is expecting at least some slight motion, and sometimes reacts as if there were movement when there is none, as when on a tripod. Just be sure to turn it off when using a tripod.

I still use a low ISO so long as the light can handle it for the shutter speed and aperture I need. If not I don't hesitate to go higher, as much as 1600, something I'd never have done with film.

Dvorak Expeditions out of Salida, CO does trips on the Rio Grande through Big Bend and the Lower Canyons downstream. I've known Bill Dvorak for many years and he is an excellent outfitter. https://www.dvorakexpeditions.com/rafting-trips/rio-grande-river-rafting/

This summer could be both dusty and hazy from fires, early fires. We have the lowest snowpack in Colorado since 2002 and the models don't look encouraging.