Lots of nice rides are possible in the Montreal area. In Montreal, you could start from the Old port area and follow the bike paths and roads that go along the Lachine canal and along the St-Louis lake, down to the west part of the island. If you ride up to Sainte-Anne-de-Bellevue and then back to Montreal, that will be a good 90 km ride.
If you go to Quebec City, there are lots of nice rides along the St-Lawrence river, for example near the city of Deschambault (route 138). You can also go up to the Charlevoix region (north-east of Quebec City) for lots of nice and very hilly rides.
I suggest that you obtain of the nice publications printed by Vélo Quebec to obtained detailed routes:
http://www.velo.qc.ca/english/index.php

Good luck