Starcraft Tent Campers

Most of those I saw was replaced with a pro to take to the sewing part. The cuts should be relatively easy? down the camper. If the roof on your Jayco is done like the roof of my starcraft, it is insulating foam with a thin layer of wood glued to it for a Celing.
What I did was detached from the wood in bulk and thin plastic sheets glued to Home Depot to the ceiling with glue panels bathroom and cut new trim to the seams and edges.

If you have a quantity of rotten wood, you'll have plenty of work to do, most pop-ups are not particularly well built and are not meant to be easily repaired.