This could be a long climb if you come from the Grenoble area and start in Vif (322m). From Vif you could either take the relatively easy and busy road up via Monestier-de-Clermont (805m) and turn up the D8 via St-Paul-les-Monestier and continue to Gresse-en-Vercors (1195m), where you turn off to the left on a minor road, where a small sign indeed (did not see it when there) says Montée du Serpaton. After a while this road becomes a bit steep up to the pass by the Croix de Gresse. The road continues 330m further up to a sender or transmission tower (1608m), where you have even better views! A nicer road early on would be to go via Miribel Lanchâtre (892m) and St-Guillaume to meet the D8 up to Gresse, but it also involves a bit more climbing.

If you come down from Col de l’Arzelier (1154m), you would start the climb on the road from Miribel Lanchâtre below St-Guillaume at the Pont Mendrant (643m) and have a consistent climbing from there.

If you come down the nice Col de l’Allimas (1354m) you start directly in Gresse (1195m) or via very nice Col des Deux (1222m) you start just below Gresse at Fruitière (1153m).