I agree with what Glam Mistress posted above. Alaska was the hardest ever, until we went to Norway/Iceland/Scotland. Take layers, so you can add or remove as needed. (for ex. instead of a winter coat we all took one of those super packable down puffers and also a packable rain shell - used both some days). Take one pair of dinner shoes (I take ballet flats) and make sure your clothes match those shoes (if you care). Pack all toiletries in the smallest size you can find. I use a packing envelope and some cubes. If he needs a dinner jacket, DH wears it onto the plane and then hangs it up. It's amazing how freeing it is when you aren't ruled by all those things people say you need.
For Alaska we wore boots/coats onto the plane. I can get more detailed if you want. We did do laundry on the ship (once in Alaska, twice in Europe but it was a long cruise). I would much rather do a load of laundry than worry if our luggage will get there, deal with heavy bags when going from place to place, and wait forever at the airport for it to go around on that circle thing. We get off the plane and go. People take way too much stuff - some of the packing lists for
DCL are pretty ridiculous. Even with 3 carry ons we were able to fit in on laptop, one iPad, a GoPro, a big Nikon and a lens, and lots of magnets for our door. So it's not like are missing anything. In fact, we have never taken a trip where any of the 3 of us wore everything we packed.