I would not consider trying to fire it up without draining the gas tank. Dri-gas might help with water, but the larger concern is pumping what is essentially varnish through the injectors. Dump the tank, open the fuel rail, and pump some new gas through. Check all other fluids and then give it a try. If she runs, change coolant, oil, all filters, plugs and flush tranny asap. A teaspoon of marvel or other top end oil in each plug hole before first start-up is not a bad idea, too. Verify you have brakes before driving away.
I am also a tractor guy and my on-line tractor buddies rescue lots of stopped machines out of fence rows and farmyards. Don't put the old gas through the engine is first rule. A lot of times folks get engines stopped for a decade to fire right up if they are not seized.
Good luck at the auction...come vist when you get it running.
On the title issue...I smell either an estate or a foreclosure in the sale to the guy who has it now. Be thorough. It could be messy.