They call those "Cruise Tours" HAL and Princess run a lot of them here in Alaska. They have both been in Alaska a very long time and have an excellent hotel networks, motor coach operations as well as priority access due their longevity, like Glacier Bay. When this question is asked most posters usually respond that it is better to go on your own, in Alaska, since it is so easy to drive here. The budget minded point out it is a lot cheaper as well. I can't disagree. But there are significant advantages as well when on a cruise tour.
We do like these combination packages for a variety of reasons. The best one ever was a safari we got from Princess which began after disembarking in Cape Town. It lasted a little over a week and took us up into Botswana and Zimbabwe. Pretty high end and not cheap but a once in a life time adventure. We are currently booked on a Princess Cruise Tour that begins in Toronto mid October, called the Maple Explorer. Takes us via coach through Niagara Falls and parts of Canada for 6 nights then Cruise New England and the east coast ending in Houston, 20 nights all total.
PS--Hope you have a great voyage and visit to Alaska. I like that you did the round trip, we did the same one time even though we live up here. Started in San Fran and ended up in Vancouver.