The Post-Apocalyptic Roadmap/Canada
Hmm... I wonder how Toronto would fare. It is a huge (for Canada) city, but... I don't think it has much military, or political importance (on a international stage). It has tons of economic importance, but I don't imagine that be as important for the initial strikes.
Perchance, Toronto doesn't get hit. That would become then a meka for survivors from both Canada (Ottawa, and our military towns/cities (especially the big ones in Quebec) and the Northern States.
With its access to the Great Lakes and then St. Lawrence (could hit up any surviving US cities along the way) and then Atlantic Ocean and major airports it could become a major Trade city from the get-go. Most likely mainly with ships and not aircraft.
To add to that, it is also incredibly multicultural we could see race riots break out in places like Chinatown as the populace finds out who dropped the bombs.