I'm the map, I'm the map, I'm the map...
Maybe the real story is that the grandfather sent a map, and the journey is metaphorical? It kind of makes me think that it's a fable that the author wrote for her son and her family, and then she thought it was really good so she published it. The art is fascinating and in a nice style. I'm not that impressed by the story because it's almost too personal for me to care about, but it's cute anyhow.
Message
Family is important even if they're far away.