Plenty of ways to come, to admire, to experience - indeed!
(Peter, this sounds great! - Until now, I did not think too much about the southern part of Spain, but agree I should do so!)
The GR107 is also called "chemin des bonshommes", and it retraces somehow the way the prosecuted cathars ("non-conformist" christian group - well non-conformist to the mainstream) might have taken to get off the country.
It goes constantly up and down from +- 700m heigth to 2500m; all the time in the mountains.
The whole way takes between 8 to 12 days, depending where you start, whether you take the shortest way or not and how fit you are...
As to the GRs in France, there a quite good guidebooks from the
http://www.ffrandonnee.fr (fédération française de randonnée), IGN maps included. These guidebooks exist as well for the main Caminos through France.