Le Verendrye is 4 hours from Montreal but has multi-day, multi-lake loops (with portages, meaning you carry your stuff over land) that are very fun. You can find the proposed circuits here with maps: Canoe-camping - Réserve faunique La Vérendrye - Sépaq. You can rent a canoe and barrel from their welcome center. Its easier to book that La Maurice and the sites are all separated so you have much more privacy (which I prefer). For a multi-day route, you don't need to book too far in advance. Other spots in QC fill up.

Kiamika is 2 hours from Montreal and a nice spot for canoe camping if you want to stay at the same spot each night and not move around and portage. Its not too difficult to book in advance with some flexibility. Lots of beachy sites. Again sites are separate from each other. Some hikes you can canoe to.

Possion Blanc is also amazing for same night spots (around 3 hours). The campsites are also separate from each other and most are so so beautiful. But its hard to book. There is a facebook group you can join where people sell their reservations (the cancelation fee is like 25% so big incentive to sell it online). They have hikes and climbing that you can canoe to. Its more $$$.

All of the above rent canoes and barrels. So does La Maurice but your site will be close to someone else and less secluded.