I chose the GR10 to get to Irun based on the Cicerone guide for the Podiensis. It’s a skeletal and brief discussion that doesn’t provide many details. Some of it is sheer rock faces, hoisting up with hands and legs. In a few places there is rebar drilled into rocks with cabling to hold to improve safety. I was alone, which is a mistake. Most GR10 hikers are going the other way and were all much younger than I. I took 10.5 hrs to get 18 km from Saint-Etienne to Bidarray. The views are incredible, absolutely, but you need to be very well trained and have high tolerance for precarious, knife’s edge hiking in very remote terrain. I certainly don’t mean to fearmonger, but you just need to know what you will encounter. And don’t go alone. I’m glad to get through it without injury. I have one day to go (Sare to Irun) and hoping the most technical climbing is behind me.