We went to Newfoundland July 2016 and took the our RPOD over. We thoroughly enjoyed the trip except for the potholes, they have signs warning of them at the pothole, then, its too late it has you. We stayed at Grand Codroy, Doyles when we arrived and when we left, nice people and park. Highlites were the Viking site, Gros Morne Park, then to Elliston were we stayed at the community park. There is Puffin Viewing from the shore/cliff and it is the root celler capitol of the world dating back to 1839. Warning travel into Bona Vista, John Cabot landed here 1497, and take Elliston Rd to Elliston. DO NOT TAKE 238 to Elliston it may appear shortest and best but we average 5mph because of the potholes and roughness, like to shook our eyeteeth out. Next on to Gander, they have a nice air museum and we learned of their importance and contribution during the 9/11 episode. We went all the way to St Johns there is Marconi's, the eastern most point and a little south is the Colony of Avolon, a archaeology site with a nice museum. this site dates to 1621, they have uncovered part of a cobblestone street, very interesting. Lots to see and do along the way. We carried 5 gal of gas with us just in case, as far as Diesel I am not sure but there were a lot of deisel rigs.
I should say we stayed at the KOA in Sydney, Cape Briton, going and coming, nice place and you can store you trailer there while visiting NL if you chose not to take it. While there allow a day to visit Fortess of Louisbourg, have lunch there and pick up a loaf of bread....yumm.
If you go have fun and enjoy, this was a little long, I hope it helps. One note, if you don't like the weather wait a little bit, it will change.