I have ridden from Bird's Creek, north of Bancroft, to Maynooth as part of a loop. It includes a long, steep climb and a lot of fast truck trafffic - my least favourite part of the ride. I don't mind hills so much but I'm the traffic can also be heavy further north.
I wanted to do the loop from our rental cottage this year but have been limited to shorter mountain bike rides in between the thundershowers. There are great and quiter paved routes in the area (like the Peterson and Baptiste roads, both east-west, and Hwy 127 between Maynbooth and Whitney) but I have never strung them together to make a century. .