I know its only August, but you can never plan Halloween too early!
Every year we have made the Arboretum our destination for Halloween fun. Our kid loved it, we loved it....UNTIL LAST YEAR! Boy did that really stink! We looked online and it looks like they are doing the same stinky celebration they did last year...so we are looking for some ideas...This year the little one is 5...suggestions?

DuPage County Forest Preserve's Danada Equestrian Center has a Fall Festival the second Sunday in October. It's not exactly Halloween but my kids loved that when they were about the age of your little one.

Sycamore has a Pumpkin Festival, complete with a parade, every year during Halloween Week.
Halloween Activities

I remember taking the kids out to Sonny Acres Farm (North Ave., West Chicago)during the fall - it's a bit cheesy but they always enjoyed it.

How about this for planning ahead? With 95% accuracy I can tell you that the newest go-getter duo at the Chamber of Commerce have let it be known to retailers that they "don't have money in the budget" to sponsor the Halloween Walk. Instead of canceling the monthly wine and cheese party in U.S. Bank's conference room, they have washed their hands of the event. The same Halloween Walk that costs them....oh.....probably zero $$$ to put on. The same Halloween Walk that brings pretty much every family with children downtown for the day. Oh...not to worry...two retailers with little to no event planning skills are picking up the ball and running with it. Running with it because they know its a valuable event. Running with it because they realize that the budget might be about $300. Running with it because folks in charge at the Chamber of Commerce...an organization in business to help retailers and recruit new blood into the retailing community...can apparently no longer run.