Oh wow, this is almost exactly what I’ve been doing with Zelda LTTP. I have it in rust now, but just finished the “first pass” you reference. Mine is still not really readable, second step is the modernizing the actual code. I’ve really struggled with needing to handhold it though, I’ll see if I can plagiarize from you!

I'm working on getting the "handholding" down to zero. Frogger is almost done and I haven't had to intervene once.