Hmm, I don't intended to stop the discussion here
If you are willing to give the W65C265S a try then you may either buy a
board (somehow a bit overprized) or built something from the scratch. Then it may help you to have a look at the
schematic of that board.
Not mentioned so far and perhaps obsolete for you: the
W65C134S. It's a 65C02 with a tiny amount of RAM (not enough) but an UART, some free port pins, some timers and a special serial interface for communication to other 65C134. If you haven't so far: risk a look
Cheers,
Arne