Next day 5€ for two up to the French/Spanish frontier at La Tour de Carol, then changed platforms and took the Spanish equivalent down the other side to Ribes de Freser (even cheaper, only 3.70€ for two).
Wednesday we took a mountain train up to Núria (alt. 1960m) and walked back down 7.5km on a narrow, rocky path. I completely forgot that I dislike hiking intensely - so won't be volunteering for any other "walks" in the near future. My poor bones :-(