Trace,
some tractors (like mine) come with one rear remote from the dealer. Some 2, some none. They can generally be added. I feel one is a minimum for utility, 2 is better.

Rear remote can also be used with a hydraulic top link to adjust the tilt on a box blade without having to get out of the seat of the tractor and break out a wrench. This is likely my next addition to my setup to complement the Harbor freight Quick Hitch I just finished adapting my BB to fit.
The NH sounds like a good deal, provided it wasn't used for 4000 hours on a construction site. (that can be a lot of abuse)
65% on the tires should be a description of how much tread is left on them.
R4 tires are "industrial" tread, which gives pretty good traction but is not as hard on grass as R1 (ag tread) tires.
The TC45 will be the next size up from the 30-40HP range tractors - in car terms, my 2535 would be a compact, the TC45 would be a mid-size.
larger frame means more weight, so more traction. it also means taller, longer, wider, and bigger turning radius.