I just got back from a trip in the Rockies. The tall and close mountains mean that the sun sets earlier than flatter places at the same latitude -- perhaps by an hour or so. The same applies to sunrises, depending of course on the precise location relative to the mountains.
Although I haven't paid a lot of attention to it, it seems to me that the sunset light in the mountains looks different than that on the plains. I'd say it's more blue (vs. red/yellow), perhaps brighter, and perhaps more direct.
I'm thinking that this might have something to do with the angle of the sun at sunset (much higher in the mountains) and how it relates to the atmosphere (thinner at that angle).
Does this really exist (or am I making this up)? If so, how does it affect landscape photography, especially as it relates to the "Golden Hour". Do locations surrounded by mountains even get a proper Golden Hour?