Carry plenty of drinking water... and another bottle with washcloth for scrubbing the face. You'll feel a lot more alert on the road for dashing water on the eyes. Stopping the car and running around it a couple of times also gets the blood moving and oxygen back into the brain. Who cares if you look like Keystone Cops? You'll improve your odds of arriving safely. And, if you can afford it, get a bottle of vitamins. Being packed into a car for a week is going to be stressful, and you don't want to be sick! May fortune favor you! Carolly