Just came back from the trip I was planing and I did manage to raise my MAMIY AFD/P25 very high up over the salt level in the UYUNI dessert. The camera worked well tethered to my MacBookPRO for quite a while (until it stopped sending images back, for a reason I have yet to determine)
Batteries where surprisingly long lasting --at least the new one of the 3 I have-- and the camera and 4 lenses (I actually left the 80mm in a box and used the other ones. was almost as convenient as a DSLR.
I have to say that the lens that earned my appreciation is the Mamiya 45mm f/2.8. It was the best angle a lot of the times and sharp as nails. The 150mm gave me good options also in terms of angle, but not at all sharp and needed high speeds or tripod to work.
35mm is a bit too wide for landscape... but good to have in the pocket..
We where from 3 to almost 5 thousand meters over sea level
I used some of my kids characters to give personalities to my batteries. This is the new one. You slide the battery in and out to turn the back on and off...