At -20C which it was last Friday I used about 55kwh from Kingston to Cornwall (there's no supercharger in between, though I guess there is chademo). Granted Sr+ is more efficient due to less weight from batteries and no front motor it would still have been really tight. And I usually try to skip Kingston and drive straight from Belleville.
I did Montreal-Toronto-Montreal trip at the same -20C this Thursday and Friday in my SR+. I can confirm, it was too cold to avoid Kingston. I did Cornwall/Belleville in the summer, but even charging at 100% at Belleville, car said I still needed to stop at Kingston if I wanted to reach Cornwall with more than 5% buffer.