For NL campsites, check out Triple Falls just outside St Anthony on the Northern Peninsula. We also stayed at Gateway To the North. Also look at Square Pond just outside Gander. Around the east, check out Pippy Park in St. John's.
For attractions, look at L'Anse Aux Meadows, the Viking settlement. Near Gander is the Silent Witness Memorial. In the east there are numerous places to see. Cabot Tower, the Geo-center, Water Street etc.
For places to eat, look up Raymond's, Mallard Cottage at Quida Vida (pronounced Kiddy Viddy).
Roads can be narrow and twisting, rough in some spots. Take your time and enjoy the scenery.