The odometer reading 44,000 could be 144k or 244k or even 344k. I dont know if the 84 G20's had carburetors or Throttle Body Injection (mine is an 87 with the TBI, & has 260,000 miles on its 350).
If it has an automatic transmission, be sure to keep the fluid level up to the proper marks on the dipstick. This isnt a big deal; but on an older vehicle you cant assume it isnt leaking a little fluid out around the output shaft of the transmission.
Ours is a conversion van -with the rear seat that folds flat-, and I find it a nice vehicle for camping.
Good Luck with your van.