They should do what lab supply companies do who have similar constraints (hard to support dealerships for niche microscopes and such, expensive to ship and time consuming to set up sensitive microscopes and such): Salespeople. Have them make the rounds to the customers like these farmers. If there is interest among the farmers in a given area, you could then organize a demo day, email your clients about it, and interested parties would make time for it, especially if you are offering them a potential out from John Deere's yoke.

It's not only about demoing. As a farmer you have very few days to get your seeds out and very few days to get your harvest in. If you machine breaks down for too long, you might lose a lot of money. So you only get machines from somebody with mechanics and a full inventory of parts nearby. You cannot wait a day for something to arrive when you are on the field, you need to get it fixed NOW.