I would like to share some of my findings and repairs with everyone as I move along with this project so others can learn like i did researching and repairing. We are new to campers, so I researched as much as possible before looking for a used sunline to take our family camping. My advise to a newbie looking for an older used camper is, they all leak. No matter what you see or hear. I am very capable of fixing or building anything and have a primitive shop/barn to work in (unheated). I found a very clean looking 1989 T1740 with 1 major water leak near the door. Knowing that I got it for what I thought was a fair price.What I diddnt know is that the wood in the entire rear of the camper was completely rotted out. Suprise!! After dismantling the damage from the interior and removing the bottom rows of siding I went to work. Rear: I ended up cutting new floor joists and sliding them in along side the existing rotted ones. The new joists are bridging 2 steel frame members and are now screwed to the floor.I used a hydraulic floor jack and jacked up the left and right rear sections on the camper walls to correct height to be able to slide the end joists in. I replaced all of the wood supports on the rear wall up to the window. Frount: Water pouring fron a pinhole in the roof.The door would not stay shut while moving the unit, reason-nothing left to the bottom of the wall from the frount to under the cabnet. Again I jacked up the wall and replaced the floor joist and wall support. I cut a section of the floor out to do this and left the door in and siding in place. By now I an getting good at this and have inspected the lower sections by loosening or removing siding. Everything else looks ok. Im just finding evedence of water of moisture on the very bottom of the inside of the luan. Im into it now so we are going all out.Check out my pics. I may not be an expert but Ill be happy to help. I keep updating as I go. Hope someone can learn something.