I have a 7.3 444 N/A 1988 with a Spicer 5 speed in it that I'm building a wrecker from (mine's a ex U Haul truck that I shortened the chassis about 8 feet) It has 4 wheel discs and air ride and in my opinion it's about the perfect chassis for a light/medium duty wrecker self leveling and 4 WD and a pretty much bullet proof driveline and engine. Mine got 12.5 MPG on the road about 250 mile trip.
Air and fuel filters are important and if your going to just going to use the factory style oil filters 3-4000 miles oil change intervals. Synthetic is usually a better choice for any lubricant if you can justify the expense. I use Shell Rotella 15-40W, but Delo is probably comparable.
I see you have lo-pro tires, hope they're in good shape because the 19.5s are about $2-300 per tire.
Should make a great camper...............
