Mike,
Dang it, that's terrible news . . . I'm assuming you seen doctors, they can do amazing stuff with surgery or replacement parts. If you get well enough, would the tractor still work for you?
I would approach selling the tractor as new. Talk to the dealer and see what kind of price they would give you in taking it back. With the lack of hours, they could sell it essentially as new. It looks like they delivered it to you and you just parked it.
If the dealer wants you to take too much of a hit, then list it on eBay and/or Craigslist. I sure would have a high reserve on it though, just guessing, but you shouldn't have to take more than a 5 to 10% hit.