'As Easy as Falling Off the Face of the Earth' by Lynne Rae Perkins

So, when the train stops in the middle of nowhere, Ry gets off and climbs a little hill so that he can get a signal on his cell phone. And then the train goes off without him ... It's a perfect storm situation. Ry doesn't know where he is,  (his parents are sailing somewhere in the Caribbean, and his grandfather isn't answering the phone). Fortunately there's a town on the horizon and fortunately,before he can get to the police station, he meets Del. That's where the journey begins.  A funny, charming and absorbing read.