Julia,
Thanks for your question!
Typically Disney will post the Walt Disney World park hours about 180 days in advance on their
website calendar, so basically about 6 months out. That does sometimes make planning where to make dining reservations based on what park you are visiting each day a bit of a last minute experience.
My personal trick is to plan out days, not in order, but in singular blocks. I plan out my
Magic Kingdom day, my
EPCOT day, my second Magic Kingdom day, etc. as standalone dates, not considering if they are at the start of the week or the end. I think ahead to where I want to eat on any given day based on location, and which park days are important for me to either take advantage of Extra Magic Hours, or to avoid them.
Then, when the park hours are published, I assemble my week, based on how the days work out best. It is kind of like assembling a jigsaw puzzle. Now for my family, after so many trips, any order of which park to visit on which day will be fine. But when helping friends plan a first trip I still make sure to have the Magic Kingdom be their first stop, regardless of park hours and weekly schedules. It is an iconic experience, and it should be any family's first stop.
One final point. The 180 day mark for publishing park hours is not a hard and fast rule. The dates have been known to come out a bit early at times. The possibility is that a few days before your reservation scheduling date arrives, those hours could be published. So definitely start checking the website daily about 2 weeks out from the day that you can start making Advanced Dining Reservations.
Now deciding where to eat? That is the best part of planning! Write me back if you need any suggestions.
Have a Magical (and delicious) Vacation!
Doug