@waltworks is the wise voice around these parts, I'd listen to what he says.
One other consideration: it depends on the local economy as well. If jobs dry up, renters dry up. Most rural areas are in a slow decline currently, but that one may not be.
It sounds like you have a lot of research ahead of you: I would not skimp on figuring out septic, well, etc. Septic can be expensive. So can wells. Well pumps need replacing every so often and they aren't cheap. (Septic too, but they're much cheaper.)
Another consideration: will you be living there? If so, you might homestead it on your taxes once you do the transfer and diminish taxes that way. And, alternatively, your taxes may go way up versus his once you transfer title because the local taxing authority may impose a new tax valuation (if there's property tax there in addition to income/sales tax).
Anyway, it's a lot to consider. You need a lot more info and financials, even though yes, the financing sounds sweet.