Thank you for your reply. I know I haven't made this too easy on myself, choosing the G3 as my first Linux box, but I'm still hoping I can get it to work.
I looked through the OpenPrinting database and found the E120n in there. However, there was no actual driver, only a reference to a "Recommended driver: pxlmono" with a link to the home page.
Reading through the page I found no link to any driver and no instruction on how to proceed, other than the "Generic instructions for: CUPS, LPD, LPRng, PPR, PDQ, no spooler". The referenced "PPD-O-Matic" did not contain the E120n and no useful information could be found on the pxlmono homepage.
I tried using the CUPS administration pages to install a printer, but the list of printer drivers available did not contain the E120n, nor was I able to use any other driver.
Any other suggestions, or tips on how to proceed with the information at hand?