Finally, an update. So in the end, we got just shy of 30" of snow. The PT-425 performed well better than I expected! I got home just in time for the snow to start. I began with the snow blade just before dark, when we had about 6". Took me less than half the time than when I used a conventional tractor last year, and also hit the neighbors mile long drive.
I waited until the next day, when we had another 12" and had to use the bucket to clear some of the huge drifts, and then went to the snow blade, which really makes it easy to push the tops of snow piles further back from the road. Later that day, I did a quick run on the last 6 inches of snow in a short time, as my skill increased with the blade.
No chains on the turf tires, and I did fine, except I got stuck in a drainage ditch twice. Quick tug from the truck pulled it right out. I don't think there is any reason to put chains on, since I have no steep slopes, and if I paid close attention to the ditches, I had no real traction problems. I spent the rest of the weekend digging all of the neighbors out - and actually drawing a bit of a crowd to watch. I even had to dig out someone's fishing boat, then pull his trailered boat out, and re-park it for him.
I was really impressed with the ease, speed, power and accuracy of the PT. My skills and confidence have skyrocketed, and I can't imagine going back to a conventional tractor for my uses. I'll post pics when I can get to them.