We usually eat a big breakfast then go for a late lunch. By 2:00 to 3:00 we get our PS for lunch.
Which is a nice time to eat lunch because everyone else is out in the park. But, if you want to see the parade in MK make sure you don't make your PS during that time.
We've never had a problem getting a PS 7 days in advance or just going right into the Garden Grill or Liberty Tree Tavern. You have to get the turkey at the Liberty Tree Tavern.