We'll darn thats the 2nd time I am wrong this year?
They are adding up fast?
I think all4500 have wood around the windows
and that is what both holds the windows
in and is the main thing that can rot out from water entry over time.
I have had to remove rotted wood and replace it with new wood on two Trill' so far.
The bunk would need to have good wood to provide solid support too.
Under the Elephant Skin you should be able to find a wooden frame all the way around,it is plywood with a sharp angle on one side to mate to the trailer walls.