I ended up looking into this a little while back as an emergency kit type thing. Wikipedia is useful - and tells me how to do a lot of things. In a disaster, I probably don't have internet. So it would be a good idea to have local wikipedia.

Zim reader was the best I could do, and still is the best at the moment. But I would be totally fine with dedicating a few terabytes to keeping much more complete local archives on my file-server if the update process was reasonably automatic (something like bittorrent would be great).