Sew light-colored fabric along the brim in back to shade your neck and shoulders and amplify breezes. Bring waterproof bags with you. Murphy's Law states that if you only lose one thing at the War, it will be the one thing that it will totally destroy you to lose. Witch hazel is a good mild antiseptic and is also cooling to the skin. It also doesn't smell or sting like rubbing alcohol.
Generic brands are just as good as name brands.
In something like a large plastic bag, pack one complete set of mundane clothing. Take out the chocks and tool kit. This way you will not be forced to unpack the whole trunk if you need the spare tire or tool kit, although, gettting your vehicle checked out before your leave should obviate this eventuality. You will be walking almost everywhere at the War. Sunburn is insidious and invidious.