Suzi,
I am the mother of 3 boys aged 10, 9 and 6.  In the past we have dressed up in "nice" costumes and even gone to fall festivals at church.  A few years ago, i noticed our church was even getting into a little of the scary side.  (Spider webs and lights in the trunks).  As a result, we stopped doing that.  I off set it by buying my kids their own candy.  Now, every year we turn on every light in the house, we even play nice, God glorifying music.  I hand out only the large candy bars and the kids tape on each bar "Jesus loves you"  I also throw in Bible tracts if I have them.    We pray for all of the children who come to our home.  We especially pray for the kids wearing the scariest costumes.  Before all of this, I plead the Blood of Jesus over my house, children and property.  My kids really feel like this is a ministry for them.  They still insist that I buy them candy, but they have no problem not dressing up and going out to get candy.
I hope you find this helpful.
Deborah W.