We were there the second day of the festival last year. It was busy, but not to the point that we would not stand and wait for the food. (My DH is the kind who will not wait more than 10 minutes for a tabel at any type of restaurant). Everything was so good. There was one dish I did not care for, but that was my own personal taste. Take plently of small change with you, i.e. one dollar and five dollar bills. Most of the food costs betwee 2 to 5.00 dollars. Most of them will take the resort card also if you are staying on property.
I can't advise you on the swimming as we live in South Florida and most of the time in the winter months we feel it is to cold to swim, whereas the northerns feel it is fine to swim.
Hope you have a great time