Well I've done both sides of the St. Lawrence on a bicycle, the 132 and the 138. Personally the 138 is prettier as you have the villages of Grondines, Deschambault, Neuville with beautiful buildings, but the 132 is not too shabby either. If you are doing a round trip, do them both. St-Pierre-des-Becquets and on to St-Nicolas. Don't forget, get off the roads and visit the villages, as there are many wher you exit at one end and come back out on the other as those raods are the ''old'' roads. I highly suggest Avenue Royale from Beauport, which is just east of Q-City all the way to Ste-Anne-de-Beaupré (Free or next to free camping just across the 138 form the basilica there). A tip. If you visit the Montmorency Falls, access it by Avenue Royale in Courville (Beauport). The charge $11.00 for parking but you can park in the streets there for free and there is no entry fee.
AND if you really have time on your hands......Orléans Island and also an hour'sdrive from the City is Baie-St-Paul and its surrounding area.
If you want to wander in these areas send me a PM.....
