If your goal is to be able to get home expeditiously and calling someone isn't an option, how about a bicycle? They make folding bikes that will fit in the trunk of any car and take up about as much room as a large pack.
Big Plus One
That's the best idea on the page. Well, that and having a dozen ways to charge your cell phone. You can make a hundred miles in a day on a bicycle. Hell, in Illinois, you could probably make 150 with all the flat land there.
If you could mount a pair of saddlebags on your bike (not that hard) I think you'd be good to go.