Been doing battle with a pair of G3 PDQs to get data on and off them. They are both MacOS 9.2 and have ethernet so I've been using that to FTP files, and at work that's fine because the PDQ there is on my desk permanently, but at home, I keep forgetting the ethernet cable, and have to drag that over after the first attempt fails because I forgot to. Truly, an old-dude-first-world problem.
I do have a floppy disk module, but only one, and I don't want to risk messing it up carting it backwards and forwards. And anyway, I fairly regularly need files bigger than 1.4Mb. An SD-PC Card adapter with various cards formatted on various early Macs sometimes works, but usually not - often asking if I want to format the unrecognized 16Mb drive (actually using 8-32Gb SD cards) instead.
USB seemed like a good idea, so I ordered an ($8) USB adapter from Amazon to try in the PC Card slot, but it wasn't recognized. It supplied power to USB devices, but no activity. Disappointing until I came across a comment that classic MacOS only installs support for devices it finds during the install, and since the PDQ has no USB, I thought I'd look for drivers online.
I found a 'USB adapter support 1.4.6' on Mac Garden, and downloaded it, dropped the contents in the extensions folder and rebooted - now the USB card is recognized and I can copy files on and off to a thumb drive.
At this rate, the PDQs will be the most accessible/communicable of any systems I have - SCSI, Ethernet, LocalTalk, CD ROM, floppy, USB and I even have 'Air Talk', (designed and built by a user over at 68kmla) which I haven't tried yet.