Bone: Out From Boneville by Jeff Smith is the first volume in a 9 volume series (plus several prequels and a separate series Quest for the Spark).
Bone is about a small creature called a Bone that has left Boneville with his cousin and friend. Fone Bone (the main character) loses his cousin and friend, manages to cross a desert and a mountain range and finds himself in a forest. He spends winter in the forest, making friends with the local animals before he finally finds a human who is supposed to be able to help him find his cousin and friend and get back home.
I'd heard this series title tossed around frequently. Middle Graders seem to really enjoy the series, and I could certainly see why. It's got some jokes that verge on being adult (and don't fool yourself into thinking that kids above 12 don't notice those) and a pretty steady adventure.
I read it very quickly, and I think it would be great for struggling readers or those who have a hard time imagining what's going on.
Middle Grade March Count : 3