Disney cruises are not the best itinerary to add on interior Alaska. It is a long way from Vancouver back north to Denali (about 2000 miles). So it would be another full day of travel to get back to Denali (You'd have to fly back to Alaska and either drive or take the train to Denali.)
If you really want to do both, it's better to look at other cruise lines that do a one way cruise between Alaska and Vancouver. Then it is easier to do some touring of interior Alaska. I love DCL and have done their Alaska cruise. But we've also done an Alaska cruisetour with Princess and that is a more complete Alaska vacation.
I agree with PP about the distance involved and the logistics of getting there.
We've done Alaska with HAL, one a 7 night round trip out of Vancouver and one cruisetour through the Yukon and Alaska, and a 7 night Seward-Vancouver cruise.
If your really set on adding Denali, you'd do better looking at other cruiselines.
If you are going to Alaska you HAVE to go to Danali. It is truely beautiful. A tribute to man getting along with nature. I know other lines like Royal Caribbean and Holland America include Denali in their add-on and they (the cruise lines) even own a couple hotels in the town. Guests travel by train from/to the port aboard customized train cars.Also Adventures by Disney goes there for we traveled with them a couple years ago. Great trip.
If I go to Hawaii, I'd like to go to Volcano National Park. Neither DCL or Aulani makes it easy.
Disney Alaska and Hawaii are "starter" offerings for locals and Disney fans, and less about travelers that want a deeper exploration of the destinations.
Perhaps one day Disney with have an Aulani resort on every Hawaiian island with easy transfers (Monorail!), or maybe DCL Alaska with integrated ABD to Denali like Princess.
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