The outside passage? Actually, it's one of the smoothest rides in cruising. Check out a map of western Canada, (starting point, Vancouver, BC) and southeastern Alaska. You'll see it designated as the inside passage (use Juneau, Skagway, and Ketchikan as landmarks or reference points). You're not cruising in open ocean, so the seas are, and hence, the cruise, is, as mild a cruise as you'll ever take. I can't recommend it enough. Beeeeeeautiful, and as calm a trip as you can have.
We are planning, within the next couple of years, to do the one-way, either northbound or southbound, Alaska cruise.