Since some time ago I wanted to do something similar to zone66x, so based in his job Ive done my own serial saturn to usb cable.
If anyone interested I can upload pcb designs, also got some spare pcbs and components.
At the moment I use cable for uploading code to saturn, I needed it because I don have dev cart and I was limited to AR comms link.
Edit: I was cleaning the car in my garage, and forget to upload one pic.