Hi there, Rachel!
If you have a 7:30 AM reservation at
Chef Mickey's (my favorite breakfast buffet, truth be told), you should have no trouble with the monorails.
The monorails typically start running at 7:00 on a "normal" day, so if you park at the Ticket and Transportation Center and ride the monorail over to the Contemporary Resort, you'll just want to be at the TTC at, say, 6:30 - 6:45 AM to address any crowd issues that might have arisen because of the special
One More Disney Day promotion. Certainly, the monorails will have started running prior to 6:00 AM to ensure Guests are at the Park for its early opening.
If you drive to the Contemporary Resort to park for your reservation and intend to take the monorail over to the
Magic Kingdom following your meal, you will definitely be in good shape.
Have a great time!
See you later, celebrator,
-Deborah B.