We stayed at Cap Chat private campground a few years back. It is not marked for a campground now tho'. We also stayed at Forillon Nat'l Park and enjoyed the stay.
If you are travelling through Montreal remember, no propane
tanks allowed through the tunnel.
If you hit Mtl anytime between 0730 and 1800 the traffic is bad. I usually haul in at the tourist info area and wait until about 1830 [6:30pm] and then head through on 20/Champlain Bridge/30 and then back to 20[TCH]. Routes are pretty well marked but all in French.
Lots of good grades out of Riviere du Loup along the St. Lawrence but I once hauled a 2000LB. pop top with a 4-cyl Toyota van that route and made it okay.
Good luck and safe journey. D.