Your trip to Niagara is pretty simple. Take I-90 east. Chicago is about 550 miles from WNY so it could easily be done in one day. All of the trip is expressway. If you do not have one, get an EZ Pass before you leave. That will save you some dollars and a lot of time.
Most will stay at the KOA on Grand Island. This campground gives you easy access both to Buffalo and Niagara Falls. Make sure you bring your passports because the best place to see the Falls is from the Canadian side and there is more to do on that side.
Things to do in the area range from the historic, Teddy Roosevelt swearing in site at the Wilcox Mansion, the arts, Albright-Knox Art Gallery, the architectural, Downtown Buffalo and the Frank Lloyd Wright homes, the old car, the Pierce-Arrow Museum, the floral, the Ontario School of Horticulture, and even the exciting in the jet boat ride into the Niagara Whirlpool.
I hope that helps at least a small bit.
