Upper Deck is a good location on the Holiday. Your cabin is mid-ships on the port side, which is a good location. I've been in cabin U38. You are just a couple decks down from "the action" areas of the ship, yet still have cabins above and below yours, which means no noise problems. I never even bothered with the elevators since the steps were quicker. A good thing about Holiday is that smaller ships mean you can get anywhere in a minute or three.
I've cruised on the Holiday twice. They offered a late night "bistro" at the buffet from 11pm to 1am or something like that. Nothing elaborate, but good and filling. I think they still do a grand midnight buffet once during the cruise, with all the big presentations and carvings. Pizza is available 24 hours a day, as is room service. Great pizza, by the way. Also try the deli they set up for lunch. Very good corned beef sandwiches and cole slaw.