DSL now is coming out with a less minimalist alpha, bundled with Gumeric and Abiword, 80+Mb. Might be worth a try? I found apt-get problematic on quite a few applications in the original DSL. I found even Vector too slow on a K6. Roll your own minimalist Debian is quite good. I used it with Windowmaker and found it perfectly adequate. This was on a 200MMX.
Alas, trying this makes you wonder why, on this old hardware, you really want to replace W98. Security maybe. But the combination of Office 98 and W98 on a really old machine, its hard, maybe impossible, to get the same combination of performance and features...
Peter