I would consider a good used tractor without a fel such as a Deere 820 or 830 or slightly larger. This appears to be for limited use and these older models are simple enough to be bullet proof and dependable. I would advise getting one with power steering then change out the fluids, filters and install a good new battery. You should be able to find a good one for about $10,000 less than a new 5045D. I have a 1973 820 which is heading for its 40th birthday and it is as good today as it ever was. In the Deere line the new 5045D is very similar to the older models, simple transmissions, high weight to hp yet simple tractors so not much to go wrong with any of them. I also think the older Ford tractors are another good choice.
Buying new and at a higher price point I agree with Bluegill2 that a 4x4 tractor could be slightly smaller and work as well. Any new tractor I would buy would have 4x4 and either a power reverser or hydrostatic transmission these are much more nimble working in the trees. I should say that the new 4520 is much easier to manuever than the older 820 or a new 5045D. My point is if you are going to buy old technology why not buy used?