If you are planning to drive North, I recommend that you come up through Glacier National Park (crossing near Babb), check the Canadian side of Glacier (Waterton Lakes National Park) and head towards Calgary on Highway 2, then to Canmore on the TransCanada Highway (spend some time there, it's a super cool city, lots of biking, hiking, climbing), then a stop in Banff and Lake Louise, and then onto the Icefield Parkway. That's a must! Know that there is no connexion at all in Banff and Jasper National Parks, but there is some in Lake Louise, in Banff and Jasper (town). There are tons of nice hikes to do in these two parks. Our friend Melissa who knows the area pretty well recommended these hikes: Cirque Peak, Parker Ridge, Fish Lake (2 days), Bow Falls, and the little stops like Peyto Lake, Sunwapta falls and Maligne Canyon. Unfortunately, we didn't have time to do any of these this time, but are planning to take some time off work next time to explore more.
Then, take the 16 to Prince George and head North on the 97 to Fort St. John, and all the way up to Whitehorse! The drive between Fort Nelson and Liard is the nicest. Make sure to do it by day as you are likely to see many animals. There are pullouts along the road where you can spend the night. There is a nice flat pullout just before Summit Lake and a few more between Summit Lake and Muncho Lake. There is no signal from Fort Nelson to Watson Lake (you'll get some in Steamboat a little after Fort Nelson). Then, no signal from Watson Lake to Teslin. Make sure to have enough fuel or carry a jerry can of gas with you since the gas stations are far and few, some are closed and some are sometimes out of gas.
I am publishing this post from Teslin, 3 hours from Whitehorse. We'll be there tonight! So excited to be back!