We have done Glacier Bay - this time going southern from anchorage to Vancouver - Carnival of course. If budget is tight - you don't want alaska! Expensive! But ohhhhhhhhhh well worth it! Best of luck in your search
Cruises to Alaska that depart from Seattle are constrained by the U. S. Passenger Services Act -- they can either (1) return to Seattle if they stop at a Canadian port en route or (2) end at a Canadian port. Unfortunately, this means that you can't get to Anchorage or to any of Alaska's interior on these cruises -- and Anchorage and the interior really do have much to offer. If it comes down to a choice, I would prefer to book an inside (!) cabin and use the savings to add on a couple days in Anchorage before or after the cruise, as there are plenty of public lounges on the ship with lots of big windows where you can watch the scenery and the best viewing of marine wildlife is from the promenades, which are below the balconies. Note, however, that this connecting to Anchorage and the interior would require departing from (or returning to) Vancouver rather than Seattle.
Beyond that, I'm going to give the same advice that I gave in another thread -- get a cruise guidebook at your local bookstore, read the descriptions of the various lines, and go with the line whose style and personality are the best match for your family.