I thought about "The Saga Begins," but that one might be a little complex. At his age, the straightforwardness of "Yoda" works a little better than a story song like "TSB."
That said, I've noticed lately that he's picking up a lot of detail from songs we listen to, so maybe I'm not giving him enough credit.
Well done, H! I remember wearing that tape out in my knockoff Walkman back in elementary school.