Great thread, why didn't I think of this?
I recommend Google Maps for getting position on a map if your GPS is working (boring answer I know). Also, I prefer the native compass over a few other compass apps I've tried.
It might be good to carry around at least the cord part of the charger. Keep the lighter portion in your car if you don't feel like lugging that around. If you can find a USB port somewhere (probably your car) and you're stranded, then you can at least charge up and most likely maintain the ability to send/receive text.
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If you're reading this, it's too late.