I don't know if they still do it, but downtown Disney also used to have a trick or treat. It was crazy nuts like 5 years ago and when we went to DTD a few months back, it had only gotten bigger... ssooo.. I don't know?
The resorts though usually offer a good time with trick or treat, they'll also run some games (or at least, years ago they did), just kind of like they normally do but halloweeny.