I think jdbnh is correct. To a collector, it might be worth $200 if all the parts are there. However, they will probably spend $2000 to $3000 in restoration if they want to make it fully functional and pretty. To somebody who just wants to sit it in their yard as "art" it's probably worth even less.
When you get into values, it always pays to know what similar items sell for at auctions. Someone who does a lot of equipment auctions/estate auctions like TBN member blueriver might have a far better idea than the average folks like me here on TBN. You might send a PM to blueriver and ask for his opinion.