the right model for the rockies (and cascades and sierras) is to be found in Switzerland/Austria/France/Germany near the high Alps. In the long run it's not going be urban development all the way up to the summits, but I would expect the Rockies to have more of the same sort of human presence that the Alps do in about 1-200 years time. The big difference is precipitation ... the Rockies are on the low side compared to the Alps, and that may take things in a very different direction.