Do I need a PS in Late September?

[Cubsd]

I will be spending 2 day at Epcot and 1 day at MGM. Will I need PS for sit down, or are crowds light enought just to wing it?

[Uncleromulus]

Most likely you can wing it, but a lot depends on what time you want to eat dinner.
At MGM especially, the "Fantasmic Dinner Package" means that places like the Brown Derby are quite full prior to Fantasmic show times--it may not be possible to just walk on in.