I’ve had what you might call a senior moment, or a Doh! moment. Andy over at the Vintage Computer Forums pointed out that Infocom games do of course come as two separate files, the game file (.dat) and the interpreter (.com) so I’ve had an interpreter for CP/M all along.
I downloaded some example story files in .z3 and .z5 format, moved them via floppy to my Windows 95 box and then via filink to the PX-8’s ram disk. After copying Zork1.com from 5.25-inch floppy to the ram disk I tried changing the names of the story files to zork1.dat. This did the trick for the .z3 files which loaded and ran, the .z5 files however would not work.
The current situation then is I need to find a way of creating my adventure and compiling it into a version 3 story file in order to play it on the PX-8. This makes sense really as the the file size limit for version 3 files is 128K.
In the meantime I continue to map the layout of the game and create object and room descriptions. I want to keep these concise, not only to preserve memory but to ensure they will suit the PX-8’s 80 column 8 line display. I also have clear ideas for a few puzzles which I hope I can implement.