There was a race along the route recently,
http://www.transpyr.com/en/01.html it looks a good route, I am planning on doing it next year (at a more leisurely pace). It is based on a Spanish route called the the transpirenaica or the two seas traverse.
I have been told that some places may need permission from the local town hall to access the route (I think its a standard tourist tax type setup, nothing dodgy) which shouldn't be a problem.
Its only a recent idea so I haven"t gathered much information as yet if I find any more I will post an update.