Yes, cars back east tend to rot more because of the salt that they put on roadways in winter. Western Canada isn't immune either, all of our HJ60's, BJ60's are rotten. The west coast (wet coast) west of the Coastal MOuntain range is high humidity and metal just corrodes here, like in the eastern part of Canada (Great Lakes influence). Once you cross east of the Coastal Mountains in British Columbia and into Alberta, Saskatchewan, it is much drier and trucks seam to last better there even though they have colder winters, etc.
It is common to do a frame swap with our BJ60's and HJ60's using a gasser FJ60 from the US with a good frame.
Where do you live?