The parade. Get a spot 20 minutes before the parade because if the ground is dry enough, the headless horseman will make an appearance. The parade is shown twice; 8:15 pm and 10:30 pm
The fireworks are great too. 9:30 pm
I like the village stage show also. It is performed in front of the castle and then immediatley after, the villains come down for meet and greets. If you have a favorite villain, watch the show from in front of the castle and then try to get in line to meet them right away.
The Haunted Mansion. There is a great ghost in front of it that you can talk to. THe ghost has a great sense of humor.
Trick or Treating. If you like candy, you will get a lot of it.
Character meet and greets. There are characters sprinkled all throughout the park and some of them are in Halloween costumes. Very fun photo opportunity.