The room with the plant NPC, that has a big column through the center. The one above the starting room. I also had the series of transitions wrong in my hint doc, so double check that. I had one extra down and right, I believe.
I also think I'm gonna just... include the dev map in the solution doc XD
Edit: Dev Map added!!! For you visual learners out there. Plus it's cool to share some of the stuff that went into making the game :3