The 4720 handles the hoe just fine - the 20 series tractors weigh over 2 tons without any attachments. It has a full subframe mount that is shared with the loader, which spans the length of the tractor underneath. The hoe (the boom, not just the stabilizers) can lift the entire rear end of the tractor off the ground and move it from side to side, which was handy to lift it off stumps I got high-centered on a couple of times. I've pulled stumps, dug holes/trenches, used the thumb to hold logs for cutting firewood, and built road with the hoe.
12 hours away? That's a long distance haul!
My hoe has sat out in the elements or in an unheated shed since 2006, so 2 years isn't a long time to be outside. No leaks from the hoe cylinders, but get an occasional drip from hoses underneath. Just have to remember to check fluid level after taking the hoe off.
The rear hydraulics on the tractor hook directly up to the backhoe inlet hoses; there was no kit as far as I can tell. If it has the full backhoe subframe and mounting bolts, that should be all you need.
Our place is outside of Richmond, VT. I think it gets too hot here in the summer (rarely getting above the 80s), so am wondering how you can stand Chattanooga?