Think your well on the right track but just wanted to mention
- Last Nvidia card officially supported in Win 3x was the TNT2 (Not sure about ATI)
- Another option for a Dos/3x PC is CF card adaptor. So if you want a pure, pure dos PC and a Dos/3x PC you can simply swap the CF card.
- Any big brand network card is fine for Win3x, only cause drivers are easier to find. NE2000 while popular in the day are only a standard not a brand. Some NE2000 cards work perfect with generic drivers, many don't.
I have gotten Dos networking up and running, but it was a pain. Now I just load the IPX drivers for games. I use Windows for networking, as its the only real reason to use 3x on my PC's (and Looner Lander while waiting for file transfers)