I began building the external display circuits on a perf board, however, I got annoyed at trying to run all the jumpers, so I made a PCB.
Attached is the schematic. It began as a simple circuit, but I didn't want to make two separate boards, and put everything on one board with the idea I'll only populate what is needed for each board.
Unfortunately I didn't create a good schematic because I used too many ports. I should have placed the connections next to the IC rather than separate the circuits with ports. Also, my pet peeve is placing too many circuits on a single page, and I did just that.
I'm uncertain whether I'll use all the "features" I placed on the board, but thought have LEDs would be cool, connectors for future troubleshooting, and a regulator should I need one rather than use the one on the Arduino.