Using twenty year old hardware is likely unfeasible to use for

>>59932993
Pretty much any major distro's past versions will work totally fine, but if you're going to be entirely offline then you might as well use something you want rather than something you think would be better. In fact you'll probably have a better experience running Windows 2000 or 98SE on it rather than some decade-old Linux distro.

And what exactly are you planning to do on your old, offline machine with the old distro?
Play old video games, right next to your real pc?

>>59933074
I imagine those does not have much modability compared to linux though, I imagine the codebase for software back them was small enough to allow modifications easily. Putting some links here:
https://archive.org/details/debian_1.3.1_iso
http://archive.debian.org/debian/dists/Debian-1.3.1/
http://archive.kernel.org/centos-vault/2.1/

>>59933121
There is no point in using such hardware for DOS and old windows games when you have dosbox, freedos and wine, unless you want to use Roland to play midis. Even then, somebody decided to "convert" some to flac http://sc55.duke4.net/

>>59932993
Start with the most recent Linux distro that supports your CPU architecture, select the most minimal installation and build from there.
IceWM is very light on resources but complete enough to substitute for a whole DE (includes panel, menu, icon tray, ...). Or try something even lighter like FVWM or TWM.

The point is that modern distros operate with relatively modern hardware specs and so are allowed to include a lot of "bloat", but some of them (e.g. Debian/Devuan) include a minimal installation that is "pure system".

Debian is also great because it supports many CPU architectures. If you like BSDs then NetBSD should run on almost anything and FreeBSD has a decent hardware support, too.

Internet browsing is possible in a limited way. Terminal browsers like w3m and lynx + assorted forks exist and can even display images, as well as some light X-based browsers, but, sadly, most development has been centralized around big bloated monoliths like Firefox and Chromium.

As for video drivers, it's a lottery. If the system was popular and easy to reverse-engineer, free drivers will be of good quality. If not, well, good luck anyhow.

>>59933074
Win2k etc. is still pretty dog slow on old machines but runs better than most linux except tinycore. Don't know how old you can with tinycore. Oldest I've tried is a pentium m. Win2k is fun in a vm though with a ram drive in the vm on a modern processor.

>>59932993
There's always some obscure up-to-date distro that can run on this. Linux is great in that regard. You sacrifice eye candy for functionality, but a guy just got his linux boot to 5 seconds on newer hardware, I suppose you could run puppy linux on most of these machines. Or at least linux without a GUI (which has a shitload of uses as well). PLUS you get to be online.