Thanks again for all the input.
Kayaker’s suggestion is very sensible, to look at which focal lengths I have previously used with my crop sensor zooms. Converting to the FF equivalent, about 40% were near 35mm, another 40% were near 28mm (as wide as I could get) about 10% were near 50mm, and the last 10% were near 85mm (as tight as I could get). Clearly the wider focal lengths are the most important.

Neuroanatomist, the panorama looks great. Did you manage this handheld? When I practice handheld I occasionally produce a set that cannot be merged with good sharpness. Maybe more practice could overcome that. A tripod is not practical for the trips I plan.

I do photograph people on these trips, but the goal is to include a generous view of the surroundings. The focal length for that is usually around 35mm.

I own and really like the EF 24-70 F/2.8 II, but the lack of IS is a drawback paired with the RP rather than the R5. The RF version of this lens with IS is 10 ounces heavier and seems pricy.

The good advice from all of you has me thinking about trading my EF 16-35mm f/4 IS for the RF 14-35, then using that the main lens. When the adapter is considered, the trade would save 6 ounces weight and about 1 ½ inches length. Sometimes the wider field of view might be handy. The biggest drawback is that the RF lens is not so sharp around 35mm.

More for me to consider, but I take from all of you that 35mm as the widest lens could be a problem.