That makes sense --I didn't even think about checking the .tkp file. I'll look into that. I don't think you are missing the issue--I was just imaging things like destructible terrain or anything that would make changes to the original map. The .tkp sounds like it would have anything needed for that.
Regarding the screenshot, I cut off the edges of the image, but there's a wall surrounding the whole map, and that's what's flipping the inside/outside.
I don't know if the rules are putting the wall there or how I'm rendering it. Either way, it's probably fixable on my end. Here's the ASCII version for what it's worth.
I have a project in the works where I'm hoping to use some of this, so I'm sure I'll bump into other ideas/issues.
Thanks for your time!