<p>I might be an exception here but I have never worked on a team with more than three developers and / or five people. Still we could manage to get the job done (somehow).</p>

<p>Is there a software development process which fits this "extreme" scenario? And, if you work as a standalone programmer is there something you can adapt to your daily life to make it more predicatable, coherent, documented and still get the job done?</p>

The
agile methodologies
are a good starting point because, imho, they are better suited for small groups.
As for keeping your personal working pace I'd recommend a method based on TODO lists and some tool like
Task2Gather
. You might want to look at
GTD
, too.
Things I would never give up even for a team of me:
source version control
backups
TODO
unit testing/
TDD
code documentation
refactoring/code reviews