While any new port is difficult the structure of the Linux M68K kernel tree is very well designed and delivers on its intention to allow easy portability between M68K targets. Several sections of this code are (rightfully) now being used cross architecture as well as cross platform.
Making a free software port work seems to be about having a small number of people willing to take the project the first 50% of the way. Once you hit this point the project gathers momentum of its own accord. Even when its something is pointless as Linux on a Macintosh II.
Lack of documentation is only a hinderance. It will not stop determined people exercising basic rights to use and operate property they have bought and own. Instead it reflects badly on the vendor who is trying to be a nuisance. If the only documentation on the keyboard interface is entitled 'Space aliens ate my mouse', someone will still find it.
Always be the second operating system port to an undocumented platform. The sterling work done by the OpenBSD/Mac team was a huge help to the Linux project. I'm also happy to say that while half of the world may sit on usenet advocacy groups throwing manure the relationship between the Linux and BSD Macintosh teams has always been one of mutual co-operation. Together we advance our detective work and knowledge of the Macintosh platforms to the good of all Macintosh users dumped and orphaned by Apple.