We have hauled our 2003 25' fifth wheel through Yukon and Alaska many times. It is still in great condition. Rear kitchen in it too, no issues. Have had the same 2002 F250 PSD towing it, and it also is in good condition.
When travelling, we're often doing only 30 mph on the Alaska Highway rather than the speed limit of 60 mph. And we always take at least two days to go over the Top of the World Highway.
Now that we live here and I commute 35 miles one way into Whitehorse each work day, I am stunned by the number of RVers I see in the summer just thrashing their trailers and toads. Maybe they don't feel the trailer hopping and bopping on the frost heaves, but really, it is common sense. Some of them would just need to check the underside of their back bumpers, which I see sparking on the highway now and then as it hits the asphalt.