I just went on the Norwegian Star, so things might be a little different, but I'll answer what I can. Not too sure about the whole room thing, because we paid for a room with a window, and got a port hole. Also on one of the lowest floors, so we weren't happy there.
We bought the excursions through Norwegian, and I liked that because everything was guaranteed. If you weren't back in time, or something happened they wouldn't leave you there. But we did know a family that did all their excursions off the ship. It was alot cheaper, and they were very pleased.
We went to Alaska, and I wore jeans every night, but one. The restaurants mainly said no T-shirts or beachwear, so they weren't very strict with jeans. Of course, mine were nice looking, not holey.
Have fun. Hope this helps!