It's over 300 km, and yes it's a bit anxiety-inducing if you don't take it seriously. I can make it on 75% of a charge if I go the speed limit and sacrifice comfort (aka the climate control is mostly off). That was at about -5 Celsius, however, I haven't tried it at -20 C. I top up at the Tru-Nor truck centre on the west side of Timmins - charge to 100% and heat the cabin ridiculously warm to begin with.
As it turns out I won't be making the trip this weekend. If/when I do the drive in truly cold temperatures, I'll let you know how it goes.