@jimbob
I've seen the price steadily rise of the past 5 or so years here in Colorado...and either deals are being made or a lot of these older Dodges are selling for close to their asking prices. Either way I don't know...but good condition trucks are becoming more and more scarce! If anything the old trucks are easily starting to surpass the '80s and early '90s trucks (except for Cummins models of course).
@macho781988
Salt on the road causes rust...water alone won't cause rust as the paint protects the metal. Colorado uses sand on the road...not salt. So unless a vehicle has sat neglected for years, never had snow removed off of it, or has damaged panels where water could get at the metal they tend to be pretty rust free.
Also, the underside, frames and such tend to be much easier to work on than those found in the rust belt. My '93 W250 lived in the mountains it's whole life -- at a ski resort -- no rust, nada. I did shocks this past weekend and was able to brake the nuts with minimal force (no heat, PB Blaster, etc) on a 24" breaker bar. How many trucks from the rust belt would be that easy (a '93, '78, whatever!)