"Have any of you pulled from the lower 48 up to Alaska with that mileage on your truck?"
My 2009 Silverado with Duramax has just about 100,000 on it. Murphy's law apparently means that all sorts of sensors fail or begin to fail at 100,000. Never had any problem with the iron, just the computer gizmo's.
I drove this truck from Katy to Anchorage in 2011 with circa 75,000 miles on it (limited use since then obviously) and in November of last year pulled from Seattle to Los Anchorage with a 5500# boat behind it. Recently pulled an equipment trailer with circa 10,000#'s from Los Anchorage to McCarthy and back (circa 700 miles only, but a pretty tough road). No problems making either trip....just sensor's needing to be replaced in between.