Faith and the Electric Dogs by Patrick Jennings
A fun, quick, read (I'd recommend for third to fifth grade) told from the point of view of the main dog character in the story, Edison or Eddy.
At the beginning of the story, we meet Edison on the street where he runs into a little girl (Faith). From there the story takes off, we learn that Faith has moved to San Cristobal de las Casas with her Mom, who just married her step-dad, Hector. Faith doesn't like it and doesn like having to learn Spanish. Instead of trying to fit in, she gets the idea to build a rocket ship to try to go back to her old home in San Francisco, CA.
On the way, there's a big storm and Faith and Eddie crash on a bone-shaped island somewhere in between Mexico and California. Eddie makes friends with the wild island dogs who lead them to an old man who has been marooned on the island for over 50 years. From him, Faith learns a valuable lesson that home will always be where you are.