Hubby and I took the Alaskan cruise last year and took about 2,500 pics. There is so much to see and a good zoom on your camera is essential. But I know that when I zoom in with my digital the resolution drops to the lowest dpi. Most of the time you will not get close to the wildlife. Even on the tours there is a legal limit to how close they can get so most of the time you will be working with the zoom.
Something that I found annoying was the refresh time between pictures. Find a camera that has the shortest time between takes. It was really frustrating to have to wait for the camera to be ready for the next shot while the whale was disappearing below the waves.
If you haven't booked your tours yet the Wildlife Quest at Juneau was amazing. Definitely worth the $$$.
In Skagway we took the train ride and it took was great.
There is so much to see and we wound up using all the film we took plus all I used all the space on the memory cards - take extra - you won't find them easily on the trip. Although the ships have internet access you won't be able to download your pictures using their computers so the extra memory is even more important.
BTW My husband prefers film so he took about 30 rolls and I had 8 disposables left over from the wedding and then I had my digital - still could have used more.
Ok we admit it - we went a little nuts but had a blast and all the pictures are worth it
And we used Walmart for the developing - great price and good pictures
Have fun
Aspire to inspire before you expire