Take everybody's prescription meds and OTC personal items, eyeglasses,camera, batteries, chargers, etc. Have snacks and a small cooler with drinks for munching on the way. If you have a GPS take it, may come in handy. Trip-tiks from AAA are nice to have.Take a basic tool kit including mini-screwdrivers, duct tape, a spare fuse kit and a cheap digital multi-meter. Rain ponchos and umbrellas may come in handy. You may not need many changes of clothes.
Stop and rest every 100 miles or so, walk around, collect your wits. Try to enjoy the process.