Don't rule out all wood framed TC's. What I mean is although my 40year old TC had rot... It was just that. 40 years old. And even with that, the rot was confined to 3 areas. Fridge vent, roof vent and sewer vent. Should those vents been maintained, there may have not been any rot at all. Now mind you, my TC had a FULL fiberglass roof and front cab over. In the newer campers, sometimes the rot is just throughout like the Black Plague. Think workmanship rather than materials. Sometimes older technology trumps newer. Just my 2 cents.