Just some thoughts. I don;t know much about the cruises. But on land, there are some very very nice packages that use the Alaska Railroad system and include Denali National Park. The train ride is spectacular. My mom booked one of the tourist cars with large glassed in viewing areas, and could not stop talking about how nice it was. Denali park has some guided activities, local attractions and should appeal to both your parents.The trains go to Seward as well, and there are excellent lodges and sports fishing there, guided and well set up. Also the Seavey Iditaride Kennel is Seward is a must see.You might also check out elder hostel travel in the state, they have programs designed to be fun and informative, and get great reviews.here are some links you can start exploring :) I am sure whatever you pick they will love this present!Alaska Railroadhttp://www.alaskarailroad.com/Default.as��Great dogsled ride, accessible for all ages, excellent kennelhttp://ididaride.com/General park info:http://www.nps.gov/dena/planyourvisit/in��additional resources for lodging:http://www.denalichamber.com/Elder Hostel in Alaskahttp://www.exploritas.org/programs/state��Also this might be good general information:http://www.travelalaska.com/
Look at:-http://www.noble-caledonia.co.uk/tour/to��orhttp://www.noble-caledonia.co.uk/tour/it��We did this trip this year. Absolutely incredible what we did and saw. Humpback and Orca whales, sea otters, sea lions, calving glaciers, brown bears feeding on salmon, standing in remote spawning salmon rivers with the fish swimming between our legs etc.etc. We even went dog sledging on a glacier before the trip, getting there/back by helicopter!It may be a bit expensive for you but in terms of a once in a lifetime cannot be beaten. Contact me if you want more help/details.