Parallel or Serial cable. Laplink, FastLynx, and even DOS 6.xs built-in INTERLNK can all transfer files over cable. Its inconvenient and not too swift, but it works.
FastLynx has the same code as INTERLNK but has a nifty interface and can use realtime compression.
An Iomega zip drive might work, since it will run off the parallel port. I think I still have one in my garage somewhere, but I might have thrown it out.
This needs to sent to ottbmare. Many new laptops don’t have an serial port but most desktops still do. I had to get a usb - serial adapter.
Since the computer is in working condition I would look in vintage computer forms for help. I think you could find some one to trade you the data on a cd for the box.