Sounds fun!
We have a Halloween party in our after school club every year, things we have done include the usual apple bobbing, treasure hunts etc. The one the kids (3-15) loved was a massive box of spaghetti all covered so they didn't know what was in it, and we had little plastic spiders and bugs in it for them to fish out, like 'worm jelly' even the older ones loved it, the one's who could stomach finding something got a treat!
We also love blindfolding them and hanging mini ring doughnuts on string and giving them a chance to get them with no hands. Cannot wait for Halloween, the kids love it!!