You mentioned 1450 above, but that isn't a current model as far as I know. 1430? 1445? 1460? 1850? Which one are we talking about? The 1430 is now a gas engine, FWIW.
Where are you located in WA? There is snow, and there is Snow. There is cold and Cold. If you are in the land of really cold and really snowy, both tractors will need oil/engine heaters for winter starts. They are hydraulic tractors and the cold oil in cold pumps is a huge drag on the starter.
I have the 1445 on 12 acres, and it does all sorts of things, really well. I don't however plow or snow plow with it. I do lots of work at just above idle. Brush hogging, rototilling, are wide open throttle. Earth moving, trenching, chipping (not a PT accessory) are medium throttle activities. 20 degree slopes are ok; higher slopes are doable, but in uneven terrain not automatically ok, as a gopher hole or a rock will make 25 degrees into 35 degrees in a heartbeat. Local conditions will govern what you can do. I do have tire chains as suggested by
@SpringHollow and they make a huge difference on slick slopes. He also suggested intake preheaters which make a world of difference.
All the best,
Peter