Red Rock is a very small Ontario township on Nipigon Bay, the kind of Lake Superior stop that makes sense only if you care about the outdoors. The old paper mill is gone, but the cliffs, cold water, forested ridges, and marina still give the place a clear reason to exist for travellers.
The best use of a spare day is to hike. Red Rock Mountain Trail climbs to broad views over Lake Superior, while the Nipigon River Recreation Trail links Red Rock and Nipigon by forest and lookout. If you only want a gentle stop, the marina waterfront gives you the bay without the climb.
Do not expect a resort town. Red Rock is sparse and practical, but as a short Lake Superior Circle Tour detour it has enough landscape to justify the turn off Highway 17.