If you really are buying and not just kicking tires, and have thoroughly researched the tractor, and looked at pictures and discussed the tractor with seller over the phone. Discussed maintenance history. Also discussed best and final pricing. Made an appointment to view the tractor. Then I have driven 480 miles one way with a trailer, and stayed overnight at a hotel locally and nearby to the seller.
After viewing and test driving the used tractor, we again discussed maintenance history. Made payment by cashier's check and while the transfer paperwork was being finalized, we loaded up the tractor and chained it down for return trip.
While I was there, another buyer of a used tractor just asked for delivery and paid extra for that delivery, because he had no trailer big enough to move his tractor.
I would emphasize to do as much research and discussion over the phone, prior to making any long drive to view the tractor. Assuming there is no hidden damage to the tractor a photo would not show (like a bad clutch or emissions issues), you are making the trip to view a tractor and purchase the tractor.