I don't think anyone has to use a sur charge dining room, but just to try one seems to me to be part of the total experience. Some will eat all their meals in the specialty dining rooms, others not. We love Le Bistro. I could never sail on an NCL ship without my Le Bistro fix and many times they will offer 1/2 price the first night or maybe a 1/2 price if you eat early. That being said, you asked about what dining rooms are not extra and about table sizes. You can choose to eat with others or alone. We usually choose to dine with another couple. It is fun to visit with people from other places.
There are 2 restaurants that are included in the price, plus Las Rambles (I beleive you mentioned being on the Sun) which serves tapas. No, that isn't a complete meal, but you can almost make it one or do like Dd and I have done. We go to Las Rambles for tapas and later in the evening to the sports bar for Tuna Melts, Fish and chips or somthing like that. There is also Pacific Heights which is a lite and lean eatery. The food is really very good plus like on all ships, there is the buffet.
I hope this helps, you made some comment about the gratuities, this is something all ships add as well as most resorts. I don't know why that would have anything to do with your decision to eat in the free dining rooms only.
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