Hi Jodi! Sometimes when I've arrived at Walt Disney World late in the evening, I've stayed at a value resort the first night to save some money before transferring to a deluxe resort the next morning. If you don't mind waking up super early, you could take a cab from the All-Star Music to the Grand Floridian at 7 a.m. so you can check in and then hop on the monorail to the Magic Kingdom. If you take advantage of
Online Check-In before your vacation, you'll speed up the check-in process. It's unlikely that your room will be ready that early in the morning but Bell Services can hold your luggage for you while you're at the park.
Another option would be to ask the All-Star Music to transfer your luggage to Grand Floridian. You could take a bus straight to the Magic Kingdom, enjoy your day in the park, and then take the monorail to the Grand Floridian later in the afternoon to check in. The complimentary luggage transfer takes several hours, but if you're planning to be in the park all day anyway, you probably wouldn't mind being without your bags until late afternoon.
Come visit us again at the Moms Panel if you have more questions! We'd love to help!