Roll out of Houdan and the woods take over: through the forêt de Rambouillet, then into the Parc naturel régional de la Haute Vallée de Chevreuse. Two small biological reserves, the Mares de Pecqueuse and the Mare aux Canettes, break up the green before the Donjon de Houdan marks the run home. Of the 62.3 km, most is unpaved, with 282 m of climbing spread along the way.
