I've installed a PRINT plugin for testing in the Wiki.
You'll see a new button on the upper right corner, where you can generate a printfriendly page online and print or download it as a PDF file or email it to someone.
You can delete unwanted/unnessecary items from the page and arrange it for your needs. Just hover over the part of the page - it will be underlayed by yellow color and you can delete parts then. i.e the "show menu".
This only allows you to print 1 page at once but it might be ok for now.
I guess I also have a solution to grab the whole Wiki and convert it into a single PDF file.
If changes occur we can announce and link it on the "Documentation changes" page like we do now. So the user can update his manual by only adding the changed pages.
Hope that helps...
Norbert