[bikesandcode]

For that route, ultimately you'd need to take Highway 99 through Lillooet, which is closed between there and Pemberton.

Or cut down to Highway 1 in the Fraser Canyon. Which is closed. As you noted, the two more convenient routes, highways 3 and 5 are closed as well.

And that's it for Canadian land routes into Vancouver. There just aren't any additional routes through the mountains.