Check out this site for a very detailed route.
http://www.hedney.com/
When are you planning the trip for? I'm looking to do the same ride and I get back to Toronto on August 25th, and I have two weeks before I head off to university.
Thanks Yan. I am going to stick to this route here:
http://www.bikerally.org/route.html
There is a great route sheet with maps in PDF at the top of this page. This route is actually from Toronto to Montréal and based mostly on the Waterfront Trail. I am pretty much going to follow the route to Prescott (about 300km east of Toronto) and then head north using the county roads to Ottawa (about another 90km). I am still working out the details of the last section of the ride.
My Friends family lives in Prescott - this should either provide a good rest stop, or I may even crash their and finish the ride the next morning.
I am planning on starting the ride just outside of Oshawa very early in the morning in August 22nd. I would gladly welcome a riding partner. Send me a PM if your plans change and you are able to leave earlier.