As other posters have said, outward, I would recommend taking snacks for plane, we went with Virgin at couple of years back and the food was disappointing and tiny portions etc. Limited Choice too. Entertainment was very good lots of films, music etc on Virgin.
When you arrive, definetely stay up, and force yourself to eat, you won't feel like it but it will help you get into the time etc. We didn't do this the first time we went to Florida and it was a big mistake, we kept of waking 3am and I couldn't eat meals at meal times as it didn't feel right. Our second visit, we ate and stayed up as late as we could, and the next morning we were absolutely fine, ready for breakfast etc.
There are some great restaurants in Florida, we liked Texas Steakhouse, and Sweet Tomatoes, a healthy type of salad buffet place, very fresh food and very,very cheap. A tip for you, in a buffet restaurant, you must have a new plate every time you go upto the buffet, to reuse a plate is against Florida law, honestly it's true and you will see signs to tell you so.
We were on a very tight budget when we went the last time, and took lunch with us to the theme parks, which is fine and passes bag checks, however if you plan on taking in your own food, it must be individual portions, i.e. Individual bags of crisps, rather than a share bag etc.
Coming home, we usually eat at the airport, spend any dollars we have left. The overnight flight back is not the most pleasant if I am honest, I always struggle to sleep, ear plugs and eye mask help abit.
Have you got Kwells? I thought they had been discontinued?
Have a fantastic holiday.