BC - Alberta:
Consider planning your route through the Rockies so you pass through the town of Sylvan Lake, Alberta. It's a pleasant place on a beautiful little lake about halfway between Edmonton and Calgary.
Toronto - Kingston
Take the Lakefront Trail. The route is about 90% on bike paths, paved cycle lanes, backroads, and quiet highways. You will need detailed and up-to-date maps to find your way. Prince Edward County (the region east of Napanee and south of Belleville) is worth meandering through. Don't miss Sandbanks Provincial Park with its brilliant white beaches and dunes.
Quebec City and east:
You can follow either the north or the south shore of the St. Lawrence River, and take a ferry to the other side from several places. I have only ridden a little on the south shore, so I cannot comment. The north shore route is spectacular. From Quebec City, follow av. Royale for about 50 km to Charlevoix, the region where the Laurentian Mountains meet the St. Lawrence River. This is one of the most beautiful areas I have ever biked through, but be prepared for hills. There are a few 20% grade monsters, although the steepest I encountered were "only" 18%. (With a granny gear, I had no problems with the more common 12% - 15% grades.) In eastern Charlevoix, in towns like Baie St. Paul, St. Simeone, and Tadoussac, the whale watching is great.