3. Never lose cell service of WiFi
Some manufacturers will let you use your car's antenna to boost your phone's signal, and some cars are actually rolling WiFi hotspots. If yours does neither, aftermarket signal boosters like this will keep you on the grid even when you start to hear dueling banjos.
Note: Technically speaking, it's illegal to roll up to a fast food place and use its network from the parking lot. It's called piggybacking, and while you'll almost never get in trouble for it, it's a good idea to be aware of any law enforcement in your area. Or just go inside and use it as a customer.