Welcome, and congratulations, John!
First, get it thoroughly clean inside and out. Your dirt is cleaner than anyone else's.
Second, make it safe to tow. Check axle
, bearings, brakes
(if equipped), running lights
, wiring harness, coupler. While you're at it, inspect the frame carefully for cracks, especially under the front of the cabin where the frame bends into the tongue and around the door.
Third, check for leaks
and deal with what you find. A garden hose with a sprayer is helpful if the weather doesn't cooperate. Make sure you look inside the cabinets and benches around the perimeter of the shell. Water can enter at a window and run behind the insulation and come out at the floor. You may have to reseal windows
and/or vents. At this point you hope you don't find floor rot from long-neglected leaks
in the past.
Fourth, determine what works and what doesn't (appliances, plumbing, AC and DC wiring). You don't need to fix everything at once- you can bypass non-functional components (i.e., use an ice chest in place of a broken fridge). Just make sure there are no hazards, such as leaking propane
The rest, including the fun cosmetic updates, you can deal with as time and funds permit. Just don't let renovations keep you from using the trailer- it doesn't have to be perfect to have a good time camping!
Member Ian G. has written a helpful guide to common issues with old Bolers: Boler Buyer's Guide