Cruising is my favorite way to travel, I absolutely love it. It's fun, the food is great, there is entertainment, you get pampered the whole time. It is well worth the money that you spend.
Alaska is one of my favorite destinations for a cruise, it is beautiful. The sites are so amazing, it is something you will never forget.
For an Alaskan cruise, I really think it is worth it to upgrade to the verandah. It costs a little more, but you will get some amazing views and you have a private area to go out on while docking and things, it is really nice.
Alaska cruises are a little more popular among slightly older people, but I love them, they are wonderful. Princess is a really great line for Alaska cruises, if you are wanting a ship with fewer kids and more adults (mostly seniors) Holland America would be a good choice.
I don't think that you would regret a cruise to Alaska. They are wonderful!