New York has some tricky laws on farm and farmland properties that really make sales of these properties difficult without professional assistance. I definitely do not recommend a land contract sale without such assistance.
In my case, the buyer assumed the mortgage (allowed back then) gave 50% down on the balance of the sale price and I carried the rest. The big down payment assuaged my misgivings. He made the first month's payment, was late on the second, then nothing. When I resold it I managed to recover my costs. Never again.
There was discussion I believe on steffb’s other thread about the different property tax issues in New York that arise when selling farm houses and farmland. Not only should steffb consult a lawyer well-versed in farm sales but would be wise to have a tax professional involved.
And there can also be income issues to consider if steffb and/or her husband are now or soon will be collecting social security benefits.
A couple thoughts regarding what might be in the lawyer written contract. Some years ago we bought a duplex where the seller provided financing. The payments were amortized over 30 years but the contract required a balloon payment a lot earlier than that (I think it was 10 years). Also, the payments were made to an escrow company who computed the interest and provided us with the form 1098 for our taxes. I assume they provided the seller with his 1099-INT. Good luck.