I've ridden from South Bend Indiana to Port Huron, MI then up the Lake Huron east shore (awesome), then straight east (Amish area). I then entered Toronto from the north and rode some bike path almost the entire length north to south through Toronto. After that I headed east. I thought the riding from SW Michigan to Port Huron to be great riding. The road system is excellent. I stayed out of major cities.
Can not help with going to Buffalo.