Endless has a nugget of a good idea at its core: Offline computing for those
with no or irregular access to the internet using lower power devices.
I personally would start with Trisquel Mini as its comes pre-packaged with a
suite of software for music, media, and office applications. Of course these
are all pretty standard and once that is realized half of what Endless talks
about on its website is a giant nothing burger.
Before distribution I would add a selection of games that are free as in
freedom. Then comes Kiwix, which is basically an offline web browser that
pulls info from compressed files. This is what gets you Wikipedia, Project
Gutenberg, and other public domain websites offline. Beyond the compressed
file tools, I'd also make sure there was a good dictionary and thesaurus.
Likewise, I'd include some media from The Internet Archive, Libre.fm, and
other public domain sources so that the system has plenty to educate and
entertain out of the box. Drivers for printers/scanners should be included.
Then comes the really hard part: offline distribution. I really love how
Endless bills itself as an offline operating system....but can only be
downloaded from its website. I have no ideas for this, but I feel the os with
its included media should be distributed on pen drive, through the same
process additional content packages could also be distributed.