This will be a slow/moderate paced 14 day trip. Main interest will be landscapes but looking to take some shots in the towns and villages as well. Need to keep things simple and on the lighter side.
Can pick from pool of XF/IQ3100, Arca Rm3Di and Nikdon D850 and choices of various lenses. Has anyone does this before, appreciate recommendations.
I envy such a trip, and hope you have good weather. Such an amazing place, which I will never see.
If you can carry the weight the XF and P1 would be the way to go for me. Tech camera, albeit excellent optics, just adds to much extra work for me now. The optics of the new P1 Schneider lenses are as good or better IMO than any of the Rodenstocks, 32mm included (I have both the 32mm and 35 Schneider and can't see any optical differences). Problem is that the XF/3100 is not a hand held solution at least for me and at that altitude may not be for you either, you will always be on a tripod which adds more time to setup.
The D850 is a great camera even though it's not using a Sony sensor (I would have preferred a Sony sensor as I am not as pleased with the results from the D850's sensor). Nikon has excellent lenses and all or most are lighter, with VR, thus you can stop on the trail, take a shot hand held and continue. Resolution of 50 vs 100 MP to me is not a big deal anymore as I can get the largest print I need 36 x 72 with a D810 or D850. Nikon has some excellent optics, in their new glass, 24-70, 70-200 and even the newer 80-400, all of which are not as massive and heavy as the XF-3100. Also the 3100 is slow to start up, 12 to 15 seconds per attempt, Nikon is instant.
Both offer ES, full ES and the D850 ES is hand holdable at certain shutter speeds. The D850 and XF both offer shutter controls from back LCD, feature I like a lot.
The tech camera IMO will be the most limiting, but if you take it I would at least consider a Fuji X-T2 class camera or a D500 and a few Nikon Lenses for a more versatile solution.
Congratulations on the trip and looking forward to images.
Paul Caldwell