On our 4/24 Western cruise, Topsiders served dinner each evening with the exception of the first and last evening. We ate there twice during that time.
I remember the young server we had saying he just worked there at Topsiders and did not do the rotation restaurants. I think he said you have to work up to that.
I believe it was open from 6:30-8:30 and it was never crowded when we went at 6:30 or shortly thereafter. Only one section of the restaurant was used and that was the side where the youngsters buffet line was for breakfast and lunch. You got your own salad from the bar (excellent with veg. pastas, coleslaw, potato saled, etc. as well as mixed greens and toppings) and the rest was served. I had delicious rosemary and garlic chicken breasts with baked potato and mixed vegetables. Our daughter had stuffed pork chops and my husband had salmon. It was all VERY good! Recommend it for a quiet dinner away from the hustle and bustle of the rotation restaurants.
Best wishes.