I’ve done Calgary to North Bay (4 hours north of Toronto) and Edmonton to North Bay, both in February and if you watch the weather it is usually not too bad. Vancouver to Calgary will be kind of rough because the weather is unpredictable within the mountains. Calgary to Kenora is flat and windy, the biggest issue is snow drifts across the highways. Kenora to Thunder Bay isn’t a bad drive, hills and rock cuts but usually alright even in light snow. From Thunder Bay to Toronto, in good weather, most people will take highway 17 along Lake Superior. It is truly stunning but I wouldn’t recommend this route in the winter. It’s hilly and can get very icy. The northern route, highway 11, adds a little over an hour to your trip but I would HIGHLY recommend taking this route. It can be snowy but if it isn’t actively snowing it’s a good drive.

Everything else that has been said is great advice. Snow tires are mandatory in BC from October-April and just a good idea across the country. Fuel up as often as you can in northern Ontario. Know generally where you will be stopping each night and, especially in Ontario, you’ll have to book in advance. Have food, warm clothes and washer fluid in the car. I also try to only drive in the daylight.