Hi Michelle,
My family has been fortunate enough to be able to travel to Walt Disney World in both 2009 & 2010 whilst free dining was being offered. This really is a fantastic offer and a great way to keep costs down.
Depending on what dates in September you will be visiting, the park hours should be displayed prior to you having to make your dining reservations 180 days in advance.
I would highly recommend booking a
Fantasmic Meal Package which will provide you with a reserved seat for the show and can be accessed from a separate entrance which is located on Sunset Boulevard next to Beauty & the Beast - Live on Stage, without having to wait in line.
Tickets for Mickey's Not-So-Scary Halloween Party will be on sale towards the end of April / beginning of May. Once you have decided on what night you will be attending the event, I would choose a restaurant in or close to the Magic Kingdom for your evening meal.
If you would like to attend a character meal prior to the party then Chef Mickey's which can be found at Disney's Contemporary Resort would be a perfect choice. Here you would be able to see Mickey and his pals whilst dining and then once your meal is finished, take a 5-10 minute walk or short monorail ride over to the Magic Kingdom.
If you are stuck for ideas on where else to make your table service dining reservations then please come back and ask me another question.
Wishing you all a magical holiday!