Best route: Chicago to Niagara Falls late June

I would personally favor the I-94 to I-69 to cross over into Canada at Port Huron/Sarnia. This completely avoids Detroit and the crossing at Port Huron is so much better than that in Detroit.

We enjoyed staying a few days at 50 Point Conservation Area on the shores of Lake Ontario. This is a beautiful park and allows an easy drive to visit the Canadian side of the Falls.

We crossed back over into the US at Niagara Falls, NY and visited the Americans side of the Falls.