Hwy 11 from Nipigon east across the lake is very scenic. Lots of up and down, curves, rocks and trees. Its the "touristy" route across northern Ontario. The cross-country truckers take the northern route, Hwy 17 from Nipigon to North Bay, flatter, less scenic IMO. There are a few cutoffs where you can get from the southern route (Hwy 11) to the northern route, (hwy 17). Hwy 101 from Wawa to Timmins/Matheson, 655 south to timmins then 144 to Sudbury. Once your in Sudbury you have to choose 69 south to 400 into Toronto or from Sudbury, east on 11/17 to North Bay (where 11/17 spits again, 17 going est to Ottawa or 11 south to 400 then to Toronto.
Maybe cross the boarder at SSMarie and go south to Sarnia and cross back into Ontario. Might be worth looking into.