QUOTE(John WD Smith @ Apr 3 2013, 06:28 PM)
We are driving to BC on highway 84 or 15. Which mountain pass is the best one to use in mid April ?
I 15 will not bring you to B.C. It will take you to Lethbridge and on to Calgary in Alberta. If this is the route you are contemplating, then you could encounter a late winter storm. You would also have to head west from Calgary on Highway 1 also known as the Trans-Canada and again, the possibility of some wintery weather exists. The same possibility exists on I 84 that will take you to Portland and then you would take I 5 north to Vancouver in B.C.
My suggestion is to use the I 84 / I 5 option mostly because you will be travelling in the US where fuel is a lot less expensive than in Canada. I am guessing that the chance of winter getting in you way would be less as you would be heading across high country farther south.
Good luck and have a safe trip.