We cruised Feb 19-26 President's week and school vacation for many in the northeast. Although the ship did have some empty inside cabins avail, it was basically filled up because of the number of people (i.e. more families). There were 1100 kids < age 18 on the ship this week. With 4000+ guests on board, the only time it felt very crowded was by the pool while at sea.
This is about my 10th cruise, previous ones on Norwegian and Royal Caribbean; we had 3 generations traveling, 15 yr old, 50's, and 89 yr old. I don't know if it was ship's size or we hit calm weather and water but it was absolutely the smoothest ship we've been on. I usually have to wear the 'seabands' but didn't even have to put them on.
It was a great cruise on a beautiful new ship. I will re-post tips I've gotten from this board which provided me with the most help, along with some new ones that I added.