I really like the ride east of 3Rivers to Quebec, that can be a superb ride. I think the earlier part from downtown Montreal to 3Rivers, depends on your sense of humor. I enjoy it a lot, but I like endless refineries, mini plazas, and nail salons; and driving past houses for 100 km. If you are doing say the Trans Can by this point you have seen enough grass and trees and would probably get a kick out of it. But I am just guessing what a person with "CANADA" in mind, might be looking for, and it might not be that. The ride from 3rivers to Riviere du Loup (RDL) is outstanding. Not sure about the time involved, but the ride from Quebec to RDL cross on the ferry, and back to Quebec (if you have the legs for the north shore) would be amazing.

The other thing is that Quebec has a highly corrupt construction industry. One result is that the infrastructure is crumbling, or falling down. This (or normal wear) meant that a few years back all the bridges on the north shore towards Quebec City were down, and that would not have been a good deal for cyclists. Last October, when I went through Montreal, the city was worse than ever, and there were major detours all over the place. I may be looking in the wrong place, but I have not been able to find real time traffic and closure updates, but some local knowledge would be very valuable in order to avoid huge detours that could cause the loss of a day. The closures on the North Shore were 5 or more years back, so it would have been back up years ago, but there seems a constant series of closures and problems, and I never know what is going to be closed next.

I highly recommend a cycling trip to Quebec, which has a very welcoming attitude to cyclist, spectacular roads, and beautiful towns. I would enjoy the trip you have planed, if you can get some up to date info you might have and easier time, so your questions here are a good idea.