1st rule: just buy it.
If it were me, as long as I didn't have to take out a second mortgage to buy a lime green HDPE Hustler, I'd take it home with me. That is a very unusual machine you're contemplating, so you may want to put up with a few odds & ends that it needs.
Seriously, check the bottom of the body for holes and cracks. If you can jack it up, shake the wheels up and down to see if the bearings are tight and if you can't jack it up, shake the wheels side to side. Look for leaks under the transmission and engine, broken chains, sprockets, etc. anything you can see with the covers off.
Good luck with it, and take pictures after you bring it home!
Don
Stuck in the seventies- not in the swamp.
(6) Attex, a Hustler, a Super Swamp Fox, (2) Tricarts, (3) Tri-sports, a Sno-co trike, 3 Dunecycles, and a Starcraft! ...so far