Upgrading to expandable travel trailer from pop up

you didn't say what you'd be towing with.

and the bunk doors, seals, hinges and door frame area are the #1 water intrusion areas of a hybrid TT.
they are the first area to go over with a flashlight and fine tooth comb.
also check the area where the bunk door hinge is. this is often where water pools and swells the wood around the hinge or wicks into the bed platform.

your statement tells me you didn't look close enough at them.