In the 04-10 Ram trucks? Maybe bedside on the 04's but I have never seen doors rot out.
They are very good trucks, isnt there someone on here still selling one?
I would stick with 06+ I havent seen them with many rust issues at all. The 5.7 is a great engine, driveline is pretty solid.
If you plan to tow a lot I would install a trans cooler.
My 04 ram had no rust at all, it was a great truck.