I agree with most of the advice you’ve gotten here, but disagree with whoever told you that used tractors are a maintenance nightmare. That hasn’t been my experience. I have a John Deere from the 1970’s, and two Deutz tractors from the 1980’s, and while they likely need more attention than new ones would, it certainly hasn’t been a nightmare, although finding parts for the Deutz is getting to be a problem. They’re good tractors, but never really caught on, at least in my part of the country. Whether you buy new or used, I’d definitely stick with an established brand, such as John Deere, New Holland, or Kubota.
As far as size, I’d suggest minimum 45 horsepower, and don’t repeat a mistake I see a lot of people make by putting a 5’ or 6’ shredder behind a tractor that will handle one much larger. I pull a 15’ batwing behind a 60 hp tractor, and it does just fine. It may not pull it as fast as some people like to go, but I’d rather move slower and cover more ground with each pass. It’s easier on me and the equipment. I do have a 6’ mower, but I only use it for under trees and in the woods, where I can’t get with the larger one.
And I see a lot of people buy a box blade to maintain their driveway. I’m likely stepping on some toes here, but a box blade is the wrong piece of equipment for that purpose. Get a blade that you can change angles (I don’t know what they’re called but they’re similar to a large road grader, or maintainer, but with a much smaller blade, generally 5’ or 6’). While it’s more difficult to learn to use than a box blade, you can do a much better job. A road needs to have a crown on it (be higher in the middle and sloping to each side). You can’t do that with a box blade. Also, when a road gets holes in it, you need to be able to cut down to the bottom of the hole, then spread the material back out. Again, can’t do it with a box blade. All you can do with one of them is to drag loose material into the hole, and that won’t hold up. If it sounds like this is a pet peeve of mine, you’re probably right. You may have a paved driveway, or a very short one, so it doesn’t matter anyway.
As far as essential equipment, I’d also say a front-end loader, with a bucket and forks, and a mower. I doubt very much that you’ll need hay equipment for your amount of acreage. Buy your hay. If you’re going to get a post-hole digger, get a good one. My neighbor has a little rinky-dink one that won’t dig a large or deep hole. He buys 8’ posts for his corners, but then only puts them 2’ into the ground for a barbed wire fence. I’ll leave that subject now before I go off on a tangent about bad fence-building practices.