Decided to forego the corner pieces of the cabinet to leave a little more wiggle room since after edge-screwing the cabinet together it was plenty sturdy. With a bit of superglue around all the seams to help hold it all rigid, I was left with a box with a hole in it.
From there I realized I'd left most of the guts meant to go into it except the screen at my hackerspace (shoutout Freeside Atlanta!), so rather than my usual methodology of "smash all the parts in and make it go BRRRR" I took a more metered approach and filled holes and rough spots, sanded it smooth, and then installed the screen since I at least had that with me at home.
Give it a lick of paint, and it'll look like one of those fake stand-in TVs Ikea used to have in the 90s. On the inside I used 4 small pieces of baby angle iron I had around to hold the screen in the right position for the front opening. I figure this is a bit of future-proofing since if I ever need to replace this screen with similar-but-not-the-same I can just shift the brackets as needed. I'll cook up something better than ratty buggee cords to hold it on for real.
One small note for this particular screen is it had face-bezel mounted buttons, but they just barely protruded, so a quick buzz with a grinding wheel makes sure they won't accidentally be pressed against the wood. The screen powers on to the correct input automatically anyway so it shouldn't need any controls for the user.