check the bunk ends for any signs of leaks. Check the canvas for mildew, water stains, etc. Check the floor for any signs of softness and water damage. Check the ceiling for any signs of water leaks, water stains or softness especially around the vent opening skylight if equipped and around the A/C unit. Press on the inside of the roof to see if you can find any soft spots.
Get a ladder and look at the roof Pay attention to all caulking on the seems and around any openings for vents A/C etc. Look across the roof for any signs of sagging. I believe Jayco may have changed the roof construction from the earlier Jay Feathers that had a flat roof. But still check. Also check out all systems to make sure they work and that there are no leaks in the water system. Check furnace and gas system. electrical system both AC and DC.
2004 Jay Feather 25E
2001 Ford Expedition 4X4 EB 5.4 3.55 rear
2004 Ford Expedition 4X4 EB 5.4 3.73 rear