Your legs still feel fresh, and that’s exactly the danger. The first few kilometres go by on their own: out of Bilbao, along the edge of the city, where industry and residential neighbourhoods run into each other. It’s not pretty, but it’s part of the deal.
After that it gets quieter and greener. The climbs and descents stay modest; the real mountains come later. Even so, you’ll be walking for more than 6 hours, and somewhere around the halfway point you’ll feel it in your feet. Güeñes comes into view without any grand finale, just a place to put your rucksack down. The Olvidado, the forgotten route, begins quietly. Start steadily, and you’ll still have legs tomorrow.