I have made a pcb that started like yours, dropped the PS/2 port, switched the usb port to type B, added a barrel power jack, and optimized the traces a little.
https://github.com/bkw777/Geoff_vt100
...in hopes I could maybe figure out the differences dhansel made to the original Geoff firmware, and then apply them to yours, which I have not done.
Is it at all possible to incorporate @dhansel 's usb keyboard change? https://github.com/dhansel/TerminalUSB
I have made a pcb that started like yours, dropped the PS/2 port, switched the usb port to type B, added a barrel power jack, and optimized the traces a little. https://github.com/bkw777/Geoff_vt100 ...in hopes I could maybe figure out the differences dhansel made to the original Geoff firmware, and then apply them to yours, which I have not done.