Lots of stuff for the kiddies.
At the movie/sing along theres pumpkin carving contest, a costume contest and such. (For the cartoons & movie it will be halloween based, usually the movie is the LEGEND OF SLEEPY HOLLOW)
Some kids DO go trick or treating around the campgrounds, but remember the kids have to understand there can be no tricks as many campers (especially retirees) aren't really prepared for the gouls and goblins.
You can usually tell the people who are particpating because most of them make it obvious. THERES lots of 'camper' decorations, some peeps get very into it.
Another tradition at FT W is the hayride being turned into a special version of the HEADLESS horseman story. (This runs for at least a month). Starts out down in 'town square' aka the hub at the Outpost Store/Pioneer Hall. A narrator dressed in period clothes starts the story of Ickbod ?Crane then they go on the ride as he proceeds to tell the story. (I've never gone on this so I don't know all the details) but they do go down a dark tree lined road where Disney has sound effects and stuff set up. At the end a REAL horse and rider appears as the headless horsemen. Anyway this is VERY popular.
Also, of course the Magic Kingdom had the party night NOT SO SCARY HALLOWEEN parties at the magic kingdom.
Anyway, there should be plenty of activities. (IF you plan to pass out candy, be sure to bring it coz Disney only sells their VERY pricey candy.)