You can also call (or stop by) Bell Services the day before your move and schedule a time for them to come pick up your bags the next morning. We've done this many, many times and they have ALWAYS shown up 5 minutes before the appointed time. I've had a couple of the Bell Services folks tell me how much they appreciate those appointments as it helps them plan better. And that they always handle the appointments first.
All the luggage transfers from all the resorts occur in one massive wave at about 1 PM. All luggage should be at the new resorts by 4pm (it's often earlier, depending on volume). As mentioned, they don't deliver unless you're in the room to receive it (and tip).
As long as you have any necessary medications, or other items with you, is a pretty simple and stress free process.
Just remember to tip on both ends of the transaction.
Steve