Your requirements are pretty broad and open to interpretation. That's why you will be seeing a lot of differing opinions based on the experience of the poster. Here's my experience. Not quite 300 acres of woods with 15 or so miles of trails. 8 or so acres of food plots. Log skidding on occasion and firewood gathering in the fall. Lot's of cleaning of tops, branches and blow downs.
I use an L3410 hst 4x4 with R4's. It's a little small for some things, and a little big for others. It can pull a 66" industrial box blade at 950 pounds. Power a BrushBull 600 medium duty cutter at 1100 pounds. Pull a 2 bottom plow or a 6' disc. It could also pull a 7' back blade. Those attachments are about all that are size dependent. Post hole digger, sprayer and others can be used on about any size tractor. One that size 34 engine hp and 28 pto, is all that is needed to maintain your property. I wouldn't want to be much smaller at all. A little bigger would be good on occassion, but would be a PITA in the woods at other times. (Ever had to walk 3 miles for a chain saw so you could get your tractor out?)
Now, if you want to run new trails, you need a MUCH larger tractor. I can push over 4" soft wood and 3" hard wood, but it's a chore. It takes a lot of time and beats the snot out of the machine and operator. But, it does leave a nice person size path. If you want a new road, paying a dozer for a day will get literally miles of road produced. And at a lower cost than doing it yourself -- even if you only pay your self a dollar an hour! Your machine costs will exceed the dozer costs.
Or you can get a 80+ hp tractor and have that extra cost to purchase, maintain etc. But the implements are 3-8X as much as those for a 30 pto hp machine. It's all a trade off between your time and your money. Just remember that maintaining is much easier than creating when talking about paths, trails and roads.