Whether you book through the cruise ship or on your own, this trip is a memorable experience. The guides freshly communicated their awe for Alaska and nature. Suiting up, waddling, zipping in the water all brought grins to the faces of all.
Although all the seats are great, if you can, let your kids take the 2 seats in the front row and the rest take outside seats. You are likely going to separate anyway. Also note: there is a back seat without a saddle that can accommodate a larger person. The saddles are for any size person allowed aboard but the back seat is a little firmer for your back, whether you are larger or not.
If your day is long enough, book the timing of this around a Yukon Discovery tour with a Frontier Excursions, and you will have a varied buffet of experiences far better and longer recalled than just the train ride. Ocean Raft can sometimes add extra outings at 7:30 am and 5:30 pm. Ask if they will for you!