Since you already have it, the first thing I always check when I'm going to rebuild one, I mainly work on Truck Campers, but I would check and repair the wheels, brakes, shocks, etc. then go to the frame, after that, then go into checking the equipment, if it has a stove, Ref, toilet,Heater, water pump, Gas tanks (propane)....Repair or replace as needed, On the Propane tanks, they may be to old and need replacing, on the gas hoses, check for leaks, then move on to the popup, replace or replace hardware, then the top....
If you are good with your hands, you will have fun and know everything about your popup...I have taken a few Truck Camper total apart, even replacing the sheet medal, not much to them after you get in there....Good Luck..
Rich and Angela, Lab Dogs, Ruben, Ace
2015 Voltage V3895
2006 Lance Truck Camper 1181
2019 GMC 3500HD 4X4 CC DRW LB Bags Husky 26K Hitch Can Am Commander 1000 ATV