[twmiller]

Also own a Mac SE/30 and pretty much went through the hoops that the linked article did, only I did all of it myself. I also picked up an ethernet card for it because I had a retro-computer connection who got me one for a really good price (like, an AMAZINGLY good price). Otherwise, the network adapters for the SE/30's PDS slot are pretty rare and usually very expensive.

A far less expensive option is to get a Pi Zero, a USB-to-serial adapter, and a Apple-to-9-pin null modem cable. You can set up SLIRP on the pi running linux and then use a PPP modem driver to connect to the internet on the se/30. You're stuck at serial port speeds, but honestly for most of what you want to do on a computer this old (irc, bbsing, file transfers of se/30 sized files) it's actually pretty solid. I use the pi zero / serial interface for a bunch of my old computers that don't have proper network adapters.