Do NOT take the Arctic Pacific Lakes Provincial Park route. Mackenzie named what is now James Creek the Bad River for a reason. Take the Giscome Portage Trail (actually, following the roads would be easier) at Hubble Homestead to Summit Lake and paddle right through the Rockies on Williston Reservoir. This is the route Joe O'Blenis took, and the link below will take you to the first leg of his journey:
http://www.clippercanoes.com/kitimat-to ... -columbia/Here is another thread with the same question, but it only got one answer. Turns out Joe O' crossed Canada in both directions
https://www.myccr.com/phpbbforum/viewto ... 05&t=44770Yukon - Porcupine - Bell (Rat) - Peel if you don't mind a more northerly/Alaska route.
http://parkscanadahistory.com/series/ch ... s19-1e.htmLiard River is scary, but it was travelled and opens a few options.
Yukon - Pelly - Finlayson - Frances - Liard
What I've seen of the Rancheria River (Liard watershed) from the highway looks navigable, and it is just a hop, skip, and a jump to the Swift River (Teslin/Yukon watershed). Rancheria is small enough that it may end up in beaver ponds & tears, I don't know.
Stikine (also scary) - Dease - Liard
Google Mike Ranta, who has gone across Canada twice recently. I know I saw a map of one of the routes he took through BC
Good luck!