We visited Niagara Falls for a week in late September and got a great room with a super view. As a child we used to go to Niagara Falls all the time, it was about the same distance away as Mackinaw and there were train tours that left from Windsor so we only had to drive across the border. However since 911 the borders have gotten alot stricter which means long lines and waiting periods. Probably will never go back to the way it was but it certainly affects where you want to vacation.
Anyhow highlights of this trip are the falls, we visited both the American side and the Canadian side, although we stayed on the Canadian side. In addition, Mary rode a trolley car over a whirlpool while James and I watched. Had to be a thrill for Mary though.