Keep going North when you get to Barrie, and you will eventually find Awenda Provinical park. Its easy to get to from Toronto, fairly close at 180 km, and offers many interesting sites, including a shipwrek, dog friendly beach, camping and great hiking. What is not to like.
Charging is mostly around Barrie, ON. We usually opt for an electric campsite so that we can charge the car, but Scotia bank hosts an EV connect charging station in nearby Penetanguishene. Barrie works for us, as the kids usually get hungry by then, and its reasonably convenient with several stations that work with our 2018 Leaf.

We went to view the fall colors. But alas the weather was not with us, it was still a lovely visit, but the crew rebelled and we wound up staying in a hotel. There is a Quality inn in midland that does have a charger, albeit not the cheapest one on the block.

After a lovely hike around Kettles lake, and after exploring the Beach (in particular the dog friendly beach), it was time to head home and dry out after a wonderful trip.