Invest in a good map. A detailed map is worth the money. In the US, look for a Rand McNally Map Book of the United States at truck stops. In the UK, look for an Ordnance survey map (ideally not explorer, though better than an A5 national map), these can be borrowed free of charge from libraries. It's what cross-country truckers use and it denotes rest areas, truck stops, and service stations. If you need a free map, though, find a tourist spot (hotel, airport, bus station, tourist information booth) and pick up a pamphlet that has a decent map inside. State welcome centers on interstate highways also have free highway maps for their state. Rental car places tend to have the best free maps. Look for a map that shows road numbers, rest areas, and gas stations.[1]