When Jonathan and I set off from Hendaye, we were determined to hike the HRP. We had studied our maps, traced the route and were mentally prepared for several days hiking before any resupply. Our approach changed at the end of day three. On day four we set off on the GR10 and never looked back. We sent all the maps back home. From then on we relied on the GR10 blazes (white rectangle over red rectangle) and a small guide (with occasional compass and altimeter checks).
Some of the blazes were easy to spot because they were freshly painted others were not so clear. In any case, this made days in dense fog much more manageable, for example while we were still following the HRP some landmarks used as reference points were no longer visible due to the cloud cover; even with a compass getting lost was easier than you can imagine.
The biggest disadvantage on the GR10 is the amount of goudron (French for pavement) you are forced to walk on. On the HRP you have fewer resupply points – but this also means less pavement. Scree ranks higher than pavement in my book – it’s millions of years old and surrounded by beautiful scenery and far from any car fumes. Le goudron is laid down every few years and guarantees to lead you to the civilization you’re trying to escape.