Nightmares of the past! Luckily, we now have enough customers with 'real' networks that we don't have to deal with Win9x peer networks anymore. Having been there, done that, I feel the same way. I truly feel sorry for the small independent guys who have to try and support this junk, the fact that it works at ALL says something about the Win9x architecture (good or bad, that is the question!). Cover all the bases, like you said, and you will have at least a chance of success. Don't, and even though the design is probably customer driven, YOU will be the one getting the boot. Nature of the beast.
One minor note - a Laserjet 2100 is not one of those junky Windows printers (which I would not touch with someone else's 10 foot pole), the 2100 actually is a very nice printer for smaller volumes (mine's been chugging along for years).