Paul,

take a board, which contains connectors, making the address bus and data bus (concretely spoken mixed data and addresses AD0-AD7) accessable to outer world. Also, /RD, /WR, /PSEN, ALE and RESET should run to this connector. Otherwise you could not expand the board with your individual applications.

It would also be a good idea, to run the Port1 lines and some Port3 lines (/INT0, /INT1, T0 and T1) to a separate connector.

Then you have maximum versatility.

Good luck,
Kai