Beaucroissant and Renage lie in the green hill country of the Bas-Dauphiné, between Grenoble and Lyon, near the little town of Rives, and not far from the Lac de Paladru, which is why the point is tagged for swimming. The lake is a glacial one, about five kilometres long, with clear water, a few beaches and shallows that warm up quickly in July and August, and the water and woodland setting make it a favourite with the people of Grenoble and Lyon. Entrance to some of the beaches is charged in season.
Voiron, a town of about twenty thousand a short distance to the east, is the larger place for fuel and supplies, and it is the home of the Chartreuse liqueur. The monks of the Grande Chartreuse monastery, high in the mountains beyond, make the green and yellow liqueur from a secret recipe of 130 herbs, and the distillery cellars in Voiron, said to be the largest liqueur cellars in the world, offer tours and tastings. The Chartreuse massif, a block of limestone cliffs and forests, forms the skyline to the east, and the road toward the monastery is a lovely ride.
Around Renage and Beaucroissant the country is gentler: rolling fields, walnut orchards, ponds and small villages with stone houses and tiled roofs. The Dauphiné is known for its walnuts, which have their own appellation, and for gratin dauphinois, a potato dish baked with cream. Roads wander along the valley floors and over low ridges, with easy corners, light traffic, and a surface that is mostly smooth, with the occasional patch of gravel on country lanes.
The Alpe d'Huez and the Oisans, the destination of this long ride, lie further south, beyond Grenoble, so treat this spot as a warm-up or a cool-down. A swim after a day on the road is a fine thing, so pack a towel. Summers are hot and thundery, and early autumn gives the best light. Watch for tractors and slow vehicles, especially at harvest time, and for school traffic near the villages.