Lee, a trip like that would cost more than a couple of body parts, I'm afraid. Radisson wouldn't offer that train trip as a post-cruise, because Lake Louise is in another province of Canada, and it's a LONG way away from Vancouver. (Or I don't think they would offer it)

I'm not sure why they are disembarking in Whittier now instead of Seward, but the airport for both of those would be Anchorage. I drug my trusty atlas out, and it looks like Denali might be almost half-way between Anchorage and Fairbanks.

As to which way is preferable, I've only flown out of the Vancouver airport once but don't remember it fondly. Flying into Vancouver is bad enough, I'd personally rather fly out of Anchorage (or Fairbanks) because of them being in the US; that would avoid a couple of the many holdups.