After sourcing an RGB cable for my Sony KV-1311CR display, I was able to check out a little bit of the functionality of the original PC-8801 computer from Japan! More work to do still, but it's a start.
Here's the video where I first got the computer:
https://www.youtube.com/watch?v=bKHMN7TeMdk
Background music is "All Is Good Again 2" by Magnus Ringblom