Yep, I think a usb car charger should work just fine. I love to camp, so I have an inverter. Plugs right into your car's lighter port and you can attach a regular house cord to it. Probably more than you would like to spend though. However, having one of these when camping comes in really handy! You can plug in smaller stuff, like chargers, lights, etc. I always have rechargeables for my flashlights, too, so I can charge those up if need be!
Definitely test first though and make sure you bring enough juice and cartos, or whatever you are using. Most of all, have FUN!!!!