Last summer I rode from Buffalo NY to the ferry to Kingston ON. Rode from there to Niagara Falls through Toronto. Summarized that trip at this link:
Bike Tour near Lake Ontario and part of Erie Canal - June 2024

I left the Waterfront Trail for most of the Toronto area, rode on roads instead. But otherwise mostly stayed on the Waterfront Trail.

I felt that the Ontario Provincial parks were very safe. I really liked Darlington, but Bronte Creek, not so much. But on Bronte Ck, I got one of the last sites available so it was of course one of the worst sites they had. They had some nicer sites that were already taken.

There are not many places to camp, so if you are camping at campgrounds, you may want to make sure that they still exist in your initial planning. Some that I planned to stay at that were on my map no longer existed.