Newfoundland is about 108,000 square kilometres, close to the size of Iceland and larger than Ireland. Maps flatten that. The Trans-Canada Highway alone runs more than 900 km from Port aux Basques to St. John’s, and almost everything worth seeing sits down a side road off it.
Visitors who try to cover the whole island in a week end up seeing the highway. The better approach is to pick one or two regions, book a couple of fixed bases, and let the days stretch. Weather, construction, ferry queues, moose on the shoulder, and a long conversation at a wharf will all add time you did not budget.
Fuel and groceries are reliable in the larger centres and thin out quickly on the Great Northern Peninsula, the Burin, and the Cape Shore. Fill the tank when you see a station rather than when you need one.