Stat point to the Granairon hut is Salvagny.
From Cluses, N 202 direction Taninges, then right D 907 to Samoens and Sixt-Fer-à-Cheval. (26 km from Cluses). In the center of Sixt turn right and continue to Salvagny. After Salvagny turn left (not right direction Le Lignon) and park at the end of the street.
From Salvagny, a forest track will lead you to the hut of Grenairon in 60 (!) bends. Climb through the forest of la Feulatière and steeper along the ravine of Nant Sec. Join the path coming from Vagny high over the valley of the Giffre. Continue on numerous tight bends through a luxuriant vegetation. A rocky zone precedes the Refuge de Grenairon (1974 m), 3 h 15 from Salvagny. In summer, you acan shorten the way by using the chairlift of Vagny.
From the hut, climb direction the Frêtes du Grenier, a strange ridge landscape. You pass the last rock, the "Cathedral" (2531 m) and arrive at the Plan du Buet, a flat rocky comb with a lake (2543 m). By fog it is very difficult here to find his way through.
From here, don't follow the path to the Mont Buet but turn left over rocks and snowfields in NE direction to the ridge of the Cheval Blanc (NW summit). Follow the crest to the highest point, the NE summit.
Telescopic sticks. Crampons are often useful.