Hi Mattie,
I know it seems weird to plan where you'll be dining 5 months from now, but I highly recommend making at least a working plan. Remember you can always change reservations as your itinerary evolves. Some of the more popular restaurants fill up very quickly, and during the busy month of July, it can often be impossible to get a table without making a reservation several months in advance.
So, yes, I would plan out your trip in more detail. It doesn't mean you need to plan minute by minute - but plan which parks you want to visit each day. Look at the calendars and see if there are any shows/events that are specific to a day. For example, if Fantasmic! is only performed on a Thursday evening while you are on vacation, you'll know that you want to be in Hollywood Studios on that night.
Also, take into consideration Extra Magic Hours. Some people love using them to extend their days, while other people avoid parks with extended hours since they are often more crowded during regular hours. You can find park hours for your stay by clicking
HERE.
Likewise, if there is a specific restaurant you want to dine at - say Cinderella's Royal Table - and you can only get in on Monday at lunch time, you know that you'll be spending time in the Magic Kingdom on that day.
Once you have a daily itinerary, it's less overwhelming to choose a restaurant.
Hope this helps. Have a magical vacation!