...FZ6: You said, " I maintain a mile and a half of steep private road and during the recent blizzard here in northeast PA, even with chains, it seems like I spent more time digging the tractor out than clearing snow. The older I get, the more of a hassle it becomes to get my tractor out of a jam. Invariably, it happens when working alone, at night and a mile or so from the barn."
In order to be very helpful it would be good to know --- 1) Is this a rock-base road/driveway ? 2) Do you have trees and other solid anchors all along the road or just in some places ? 3) Is this 95% a snow issue or do you often have "in the road mud hole" issues ?
While waiting to hear those things I do have one immediate comment. The R4 tires are not ideal for this. It is NOT cheap to swap (and you may well have reasons like backhoe work, etc. not to swap) but R1 ag tires have much less trouble in snow, esp where the snow tends to become ice almost the instant the tire begins to spin. You might find someone willing to swap R1 tires for your R4 set (?) Be interested to hear the rest of the story about your long driveway environment.