On one of our trips we took the Alaskan ferry leaving from Bellingham, Washington. We did this mid-May and the weather was terrific with lots of sun. The snow on the mountains made it even more beautiful. The ferry stops at various ports where you can get off and stay a few days and pick up the next ferry. It's a neat way to go!
Denali - someone mentioned taking a train to Mt. McKinley....not possible. You can fly there on a small plane out of Talkeetna which even lands on a glacier at the base of McKinley. Even the mountain climbers have to fly to the base - no train. Also stated is that the cruise lines stay in Denali. They stay outside of Denali at a hotel and are bussed into Denali. Only campgrounds are in Denali.
However, if you're lucky you can easily see Mt. McKinley while you're on the park's bus tour within Denali itself. We drove up there another year and stayed in Denali Nat'l Park 10 nights and saw the mountain 7 of 10 days. Many folks never see it. It's a hit or miss. It's so big it creates it's own weather.
I mentioned a bus tour, actually, we took the park's shuttle bus which is a lot more reasonable in price. The drivers are very knowledgeable and are experts at spotting the animals. When they do, they'll stop the bus for you to get a good look and take photos.
The best thing about the shuttle bus is that you can get on and off wherever you want to explore and then pick up the next shuttle coming by - usually in 15 minutes. With the regular bus tours you're not allowed to get off and they don't spend as much time looking at the critters. There's lots to do in the park other than the bus tour but you have to stay in the park to do them. Have fun planning!