You need to find out if the engine is free or stuck, and if it will actually run after such a long time parked in the open.
Otherwise, just as it stands - scrap iron value. If seat and batteries have been stolen, what else has been stolen, as well?
It does show promise as a useable tractor - but it doesn't take long to run away with a lot of $$'s trying to get a tractor operational again, if there's numerous things wrong with, or missing from, the tractor.