I could never get any of the Farallon gizmos to work. Furthermore, I could never get any of the Fastpath boxes to work either. They acted like they were working, but no data ever got from one side to the other. There was a third type I also tried with no success. (edit: Dayna)
There are SCSI gizmos which talk to Ethernet which should be much faster. Make sure you get a driver disk, though.
If you only want to print, the easiest solution is to have an additional Mac, such as a IIci, which you can get for almost free, and run LaserWriter Bridge. That works.
If you want to use Appletalk or surf the web, there may be an Appletalk Bridge package you can use, but I've been unable to find it anywhere.
Also, the SE series of computers can have Ethernet. I think you'd likely be happier with an SE/30 than with the Classic. It's about the same age, much faster, about the same price, and can have Ethernet.