"Not to take away from Mr. Bell's series of color photos from the trip, here's some of the stuff I shot on Kodak "Tri-X" (I've heard the new formulation isn't as good as the original run) 400 film in a Nikon N75 Body with a Nikkor 25-120 f/4 lens."
These look very good! Looks exactly like how I remember Tri-X reacting at altitude. It takes that bright, contrast-y high altitude light and runs with it like a toddler with scissors. I always thought it has a habit similar to Kodachrome of blocking up in the shadows pretty badly, but if you know that and cut your exposure by about 1/3 stop you can control the contrast a bit. In 35mm I stuck with Plus-X or K-25, Dad ran Tri-X exclusively in his 2 1/4 x 2 1/4, the larger image size made the grain and contrast more controllable, particularly with the way he prints. 35mm neg size simply doesn't allow the image resolution with the grain, the image you have is the image you have and you worked it in the darkroom with the paper contrast choice.
I think you really nailed the exposures!
SRK