It was a bit of a struggle, but with the aid of the native Linux ACX100/ACX111 driver from the ACX Project and some hand-hacking of the start_net script supplied with it to eliminate a few bonehead maneuvers, I have wireless networking up and running — WITHOUT having to use NDISWrapper — on the Thinkpad 600E with a Linksys WPC54G card. (I still don't actually have the wired Xircom 10/100 PC card working either, but with wireless working, that's a lot less important.)
That just leaves sound still to be sorted out. Once it was pointed out to me that the CS4236 is an ISA device, not a PCI one (so I was looking for it in the wrong place), ALSA installs and appears to start up, but blocks every time I try to play a sound. It works perfectly, unless you want actual sound to ever come out of the speakers. So unless I can figure out what the problem with ALSA is, I'll probably just install the full OSS/Linux from 4Front. I don't care whether the purists consider OSS to be obsolete; my entire history of sound-on-Linux experience thus far is that OSS has always Just Worked, and ALSA still doesn't.
(Side note: Gad, I hate KDE.)