The scenery north of the Soo is the best anywhere, Lake Superior provincial Park has a few nice spots to check out, Old Woman Bay, Pictographs. Whiteriver is home of Winnie the Poo bear with a nice little park, we stop to eat lunch there!
Ouimet Canyon is very cool but if you are towing you have to leave the trailer etc in a separate parking lot - tight corners and a small parking lot at the canyon. Terry Fox Monument is a must as is Kakabeka Falls about 15 Km west of Thunder Bay. Rossport is a nice scenic area as well.
Camping though - many campgrounds are closed or closing middle to the end of September, best to check the web sites for dates.