Another good thing to have on hand (I don't, yet) would be an inverter. Look it up--you attach it to your car (battery or cigarette outlet, maybe newer ones go to usb) and then you can plug things into it. Not too much, but enough to run a coffeepot or a light or hotplate. Sure, you need to keep the car running, but then you stay in the car for the ac anyway. Oh, and get a manual can opener.