If you're talking about the Pyrenees/Pireneos then I suggest a full loop - start anywhere on the loop and go either clockwise or anticlockwise around the range. Stay close to the mountains: i.e. Pamplona, Jaca, Aínsa, Alp, Perpignon, Foix, Tarbes, Pau, Oloron Sainte Marie, St Jean Pied de Port...