I don't know if you have already started travelling but I will throw in my two cents.

I live in Montreal and it is a great cycling city. There are bike paths everywhere. It is particularly fun to end up on the Gilles Villeneuve race track (where Formula One used to race) and take a good spin on the bikes. You have a lot of great references in the posts already. Get yourself a good guide to the Route Verte, which runs throughout the province.

We want to try the Petit Train du Nord in the Laurentians this year. We just bought our hybrids yesterday and this will be our first big trip on them. It is about a 200 km ride.

Have fun - if you have specific questions, I would be more than happy to help!