I know you posted this a while ago. Not sure if you're still interested. But I'm in the Cortland area and I accidentally came across several landlords of student rentals who wanted to sell. You'll be surprised how many landlords want to get out of the business, sell their properties and move to a warmer climate after last winter.
I went to the code enforcement office and asked for a list of residential properties that had code violations. I sent letters to all 30 of them. Most of the people who called were landlords.
Code violation list was not as easy to get as it should be. They act like they have no clue what you're asking and might even pretend it's harder to get than it is. But with persistence, you'll get it.
Also, people not on the list might want to sell. My own landlord found out I was at the code enforcement office and offered to sell some of his student rentals to me. I suggest you take down all the addresses of the rentals you would like to own, find out the mailing addresses through the tax assessors and mail letters to owners. I believe you'll definitely will get calls.