So for the children who come to my door, I give sandwich bags packed with candy and child-friendly Gospel tracts. Sometimes I dress as a Bible character (last year I dressed as Mount Sinai, complete with the 10 Commandments carved on tablets) and play Christian music on a boom box plugged in on the porch.
I oooh and aaahh over their costumes, interact with the parents, and tell them I hope they'll return next year. I have a Muslim family around the corner that gets the Gospel in a trick-or-treat bag from me every year. I use the occasion to spread the Good News.
If all the Christians turn their lights off and lock their doors and sequester themselves on church campuses for Halloween "alternatives," who is going to represent Christ to those children who will never set foot on church property? What other holiday sends dozens of people to your door with open hands? Halloween is an extravagant gift to the Church!