Just one way. I don't have time to do both. I'm actually starting in Ajax, likely staying in Cobourg, then Sandbanks Park, then to Kingston, and onward as described.
Since I started this thread I've learned more about the towns along the St Lawrence. Brockville looks like a nice place and I think there is a camp site in town. There is a great viewpoint that looks out at the river.
My concern now is that the routes from the St Lawrence to Ottawa that have come up so far using various planning sites look like 100km of straight roads through farmland or brush, which I've had enough of from biking Southwestern Ontario. There is the option of going from brockville to smith falls and then to Ottawa. Might add a day though.
I sure know a lot more about the Ottawa valley than when I started out. I hadn't even considered how educational just planning a bike tour would be.