MNSSHP is a good time...it consists of special events such as:
A Halloween parade(Boo To You), characters are dressed up in costumes...the parade was great!
Different version of Wishes fireworks...called Hallowishes.
When you enter the Magic Kingdom, you'll be given a trick-or-treat bag and you go trick-or-treating throughout the park at 'X' marked locations, chocolates, candy is given out.
At the park entrance, it is smokey, eery atmosphere(but not so scary!) with Halloween decor...all done in a Disney Fashion of course.
The park itself has Halloween decor throughout...very cool. Take plenty pics.
You'll notice plenty of kids and also adults dressed up in costumes!
There is a show in front of the castle, but unfortunatly, I missed it.
And of course the park is open for extra magic hours which is at least midnight.
If you have any other questions, feel free to ask. I'm sure I may have forgotten some other piece of info.
You'll have a great time!