If you want a TS meal, I would also plan it for before the party starts.
Considering the cost of party tickets and all the activities exclusively at the party, I don't want to spend the time eating dinner. In past years people were allowed into the MK starting at 4 PM with just their party tickets so that gives you plenty of time to eat before all the activities begin.
If you decide to do CS, not all of the places are open during the party. We went in 2009 and I know Pecos Bill's and Casey's Corner were open as was Cosmic Ray's although it had a much more limited menu than usual. I believe they stopped serving things like ribs around 6. Columbia Harbor House and Pinnocchio's wasn't open at all.