My choice for mass market Alaska cruising is HAL. Somewhat smaller ships, crows nest covered forward observation lounge, covered pools, more ships and itinerary options in Alaska. Summer Alaska sailings will have plenty of kids on any major line so I wouldn't worry about that. Club HAL is fine, our kids have done it many times. Polar opposite from kids clubs on Disney though. Lot fewer kids so more personal attention, arts and crafts, games, etc. Plus, Alaska is more port intensive so activities on the ship aren't as important.
I would look at one way sailings as from Vancouver and then add on a HAL Denali train trip at the end. Many of the one way sailings on various lines do two glacier days. Usually adding Hubbard or College Fjord along with Glacier Bay - all of which are "better" than Tracy Arm, IMHO.
We've also done Princess, NCL, and X to Alaska and they were all fine as well. Princess Pelican's kids club was lousy on our last Alaska trip, but we've had good experiences with their kids club on other cruises.