Hi Richard, this is the trip I'll be doing later in the year. Ferry from Plymouth with a mate, my son who has a place in Andorra will ride down to meet us, then TET back to Andorra. As I'm sure you're aware, you'll be catching the tail end of the Andorra ski season, so some of the high passes may well still be in snow. Woohoo. I'd be grateful to get some gen from you after your trip if that is OK. It is easy enough to download the route, but getting info from someone who has recently ridden it, camping, will be invaluable.
