PRESENT DAY JOCO SAYS: This is probably an even more impenetrable riddle song than Under the Pines. I forget because it’s so obvious to me that it’s about Pluto, but listening just now I realize there’s not really any way you’d know that unless I told you.
FWIW, I didn’t get Under the Pines at all until it was explained to me. I’m Your Moon, by contrast, was so obviously about Pluto/Charon. That might be because I’m a nerd, but the references to vast distances, ice cold temperatures, orbits, and number-shuffling made it a slam-dunk.