Since the MK usually opens at 9 AM on non-early entry days, buses won't be running early enough on Tuesday to get you to a 7:30 PS at Chef Mickey's. There really isn't a way to get there at that time using Disney transportation.
If you will have cars, the best thing to do is drive. If not, take a taxi. I'd estimate the cost at $12-$15 per cab, depending on how much you tip. By the time breakfast is over, buses and monorails will be running so you can use Disney transportation from there.
Enjoy your trip!