Dont worry. It will be great. There are plenty of places on the ship to get away from it all.
1. If you want sun and dont want alot of people around, walk to the highest decks away from the pool. There are usually plenty of chairs and very little people.
2. Breakfast and lunch in the dining room. If you dont like the arrangement of finding tables and the amount of people at a buffet, have your breakfast and lunch in the dining room. It is usually not crowded, the food is better and it is a very peaceful atmosphere.
3. The promonade deck is never very crowded and they usually have nice chairs to relax.
4. Get to the shows early to pick your seat and not fight the crowds. Lounges with no entertainment venues going on are usually open and empty and a good place to be away from it all.
5. I forget there is a casino on board because I dont gamble. I will eventually pass by it and say "oh, theres the casino". While a cruise ship is a floating resort, it is NOT a floating Las Vegas.
Bottom line a cruise ship is like a hotel experience but better because there is so much public space that is not used by the guests at all hours. You will find your favorite spaces and times to go to them very easily. Do not worry. You will enjoy it.
19 cruises total on all different lines including RCCL, NCL, Celebrity, Princess, Holland America and Sea Dream. Our 20th Cruise is October 2007 on the Mariner of the Seas.