Were you lucky with the weather or is it like that a lot? The light makes such a difference.we were "lucky". but also persistent. Yellowstone has 365 miles of paved roads and the grand tetons about 1/3 of that. we were there six days and out in the field 10-12 hours a day. elevation varied from 6k feet to over 10k feet and the weather changed rapidly. in Yellowstone we had rain, hail, sleet, snow and winds all in one day. the tempertures were from about 35 degrees to 80 degrees, though it was 102 degrees when we crossed the Nevada desert where OJ Simpson now resides.
it's all about the light but light at those elevations tends to be better than at sea level especially when you have cloud cover. I also shot more than 2k frames so much of the "luck" i'd say we created.