I don't think gnuite has his own route making app. Your talking about the server he runs that downloads the route for you right? I believe all that is, is just a script that automates the work of..

1) going to Google Maps
2) entering the starting: and ending: destination
3) downloading the route as a .gpx file
4) find/replace all cmt references to desc references

Essentially what you can already do manually using the gmaptogpx bookmarklet. So I don't know how helpful in having it offline since we would still need a data connection the directions from Google Maps.

Though I do apologize if there's something more magical going on.