going disagree some with soundguy with tires. tractor tires, can get rather expensive more so the rear tires, when the tire starts loosing tread. you really start loosing a lot of traction. you are working in soft soils and not in the concrete jungle of a city. and on paved roads. and longer those treads stick out form tire, more likely more traction you will get.
AG tires (R1's) generally require smaller size width rims. vs turf or loader (R3's) it is more likely you can swap tire types between turf and R3 tires. vs swapping anything but R1's for R1's without getting a different set of rims.
dry rooted and/or cracked tires with 50% tread left on tires. on a old use machine, i would have to most likely pass on. due to cost of tires may be more than what you paid for the used machine. or less you are fairly mechanically inclined and will be keeping the tractor for good amount of years to come. were getting new tires would more likely pay for themselves.
with being in maine, if my remember is working correctly, you get descent snow every year, and those turfs, tires to me would be ice skating, and no traction, you also mentioned 20 acres of woods, dealing with driveway, and other things. it is all those odd jobs, and getting in soft soil and muddy conditions, that turf tires, *shakes head no*. see about finding a tractor with R1's or R3's on the rear end. the fronts, if possibly might go with a 2 or 3 ribbed tire, vs a generic turf tire on front. 2 or 3 ribbed tire, will bite into mud when ya go to turn, vs having skies on the front and just keep sliding forward in the mud. if you looked at some old field only tractors you will more likely see the 2 to 3 ribbed tires on the front.