Just did Alaska last summer including land excursion to Denali. Trip was great.
Couple observations
1.Denali, often too cloudy to see the top, apparently only 50% see the top. We saw it from 150 miles away on the bus ride from Fairbanks and that was it. Otherwise the land trip was great and the train ride from Denali to Anchorage was great.
2. Cruise Line/cruise - I think you will find almost all cruise lines stop[ in the same cities. The difference might be in the excursions and price each offer. Be sure to consider that in price comparison's.
3. One difference may be on whether or not the large ships can do the inner passage, which I would recommend.
4. regarding cruise lines. We chose Regent Seven Seas for a couple reasons. We have used them before and liked the experience. The ships are generally smaller [around 500] and it is all inclusive
so you don't have to worry about drinks and tips. Our traveling friend's did a fair amount of research and Holland America also sounded good. Princess gets rated high for Alaska but that is a completely different cruising experience. [a couple thousand on the ship] that may work better for you with a large and diverse group.
5. Finally, don't try to save on the excursions. We found each city is fairly similar and the really cool part of the trips were the excursions in each port and they all offer lots of choices.
6. One other thing and I never checked to see if true but we were told after we got there that July is generally drier but the mosquitoes are terrible, and August is wetter with no mosquitoes.we went in August and it rained every day but it didn't slow us down although a couple seaplane excursions got cancelled.
Have fun, eat lot's of salmon and halibut.