GaryCrowell said:
. . . skip the industrial tires, they're for mowing lawns. For everything else you need ag tires.
Whoa! I'm glad some of my friends don't know that. My next door neighbor has a Case 580K loader/backhoe and a Case skid steer. Poor devil doesn't even have a mower for either one and they've both got what appear to be R4s.
For where we live, in the mountains of West Virginia, I find that the industrial tires do a much better job in the woods than ags. Where I'm at we have a lot more sandy loam and rock, than we have clay. Your terrain doesn't sound that much different from ours. They don't tear things up as bad. For loader work and for grading they are just fine too. And they certainly don't tear up the lawn like ags.
Back on subject ... the seat time that others talked about is probably the very most important thing in determining which tractor to go with. If you are going to be using it in the woods, get down on your hands and knees and look hard at the underside. Look especially at the front-end to make sure the axle is sturdy, and the steering arms, ball joints, etc., are well protected.
For what you described as far as mowing, grading, moving rocks, etc., a 30 hp tractor certainly would be very adequate. I skid a lot of pretty good size logs with a little 20 hp - without a skidding winch (I use a modified carry-all, and when necessary, a come-along). Before that, I was using a 17 hp 4wd machine with very aggressive ags. For the few things I can't handle, I've got neighbors, and it seems like I am frequently a storage lot for tractors in transition.
Good luck,
Knute