We just returned today from Newfoundland. Got off the ferry a few hours ago.
Check out the Provincial Parks of Newfoundland. Lots of dry camping sites and "serviced" sites. They have a good website with size limits for each site. They all have a dump station.
Newfoundland wasn't much more expensive than Nova Scotia. Camping season in Newfoundland seems to run till October.
Their fresh produce stands opened last week finally so you can enjoy their local bounty. Note however, that you can't bring any potatoes, carrots, turnips or other root plants onto the ferry when leaving Newfoundland.
Enjoy your trip.