Here's my advice. Continue the arrangement with the neighbor farmer for the hay. You don't have the time now. Ten years from now when you retire, you'll be much more familiar with tractors, your desire or need for hay etc. Don't buy a tractor today for haying in ten years. Hay bailers are complicated machines. Who's going to fix it when it breaks down and you have 50 acres mowed and windrowed and the rain is about to come and you have to go to your real job?
With 3 cuttings of hay, you might produce close to 100 bales an acre. That would be 5000 bales. Then you need to store them or sell them out of the field. That's a lot of work and a big storage barn. You'll kill you self trying to get that done on weekends and the weather does not necessarily match your work schedule.
At least, that's what I would do.
Then consider, you need to build/maintain a driveway, so a heavy duty back blade and front end loader. Are you going to make a garden area with the tractor? Are you going to grade the land or your build site. Are you going to use the tractor for mowing lawn around the house or have a separate riding mower?
Depends on your budget, but I would look at 30-45 Hp compact utility tractor, with a front end loader, heavy duty back blade and a rear mounted finish mower and a brush hog type mower. Then trim with a walk behind mower... get the wife to agree to the trimming. A mid mounted mower would be more convenient for the mowing task but it depends on how much other work you will need to do in the mowing season. A midmount mower while using your fel in the woods is likely going to wreck the mower.
Of course the mowing situation depends on how much real lawn you plan on having compared to rougher field mowing. And you could buy a small riding mower for the lawn and not use your tractor for that.