My first suggestion would be to look again at the length of stay passes. Make sure you are getting your money's worth (it can be done, but it's difficult to really do). Still, if it is your best choice, here goes:
When you check out of your first resort, your passes will still be good (until midnight). You get everything packed (we usually live out of the suitcases, so that is not a problem), and call for bell services to pick them up. They arrive, give you the ticket for the baggage, and then go to whereever you wish to go (keep one small bag with the things you will need). When you get there, no matter which park (theme or water) there is a locker available (for around $2). Sometime later in the morning, or early afternoon, head over to your next resort (at your convenience - remember, your luggage will not get there until around 3). Check in, and if your room is not available, they will give you a card with a number to call later to check if it is available. They are very good at moving luggage (although I did hear of one case on the boards that they screwed it up). We love the moving from one to another.
