From San Bernardo ( which can be reached by turning left off the SS36 just before S. Giacome Filippo) follow the signs for the C25 trail, taking you to the houses furthest up on the hills of the town. Here, go left on the flat trail that follows the orographic right side ( the right side when facing downvalley) of Valle del Drogo. You'll come to the alpine hut Sant Antonio. A little further ahead, you'll find the one called Caurga, shortly before which, the trail goes right and on a lovely paved pathway, takes you up the steep slope by following numerous curves. These end up on the rim of the basin where Lake Truzzo is located, blocked by the retaining wall of a damn. Going towards the left, follow along the entire retaining wall. Then continue on the trail that goes uphill and you'll soon come to Lake Nero. Skirting the lakeshore on the left, take one last northward turn and you'll come to the mountain hut.

To the Passo del Servizio bivouac 2570 m c. (E; 1 hour and 45 min.) From the mountain hut, go down along the shores of Lake Tuzzo. Following the lakeshore northwards to the Truzzo Alps at 2110 m. Continuing north, go past a rubble strewn canal to the hollow of Zocon. Carrying on in the same direction, come to the grassy rubble-covered slopes of the southern flank of Motto Alto. Leave the trailmarker for Pizzo Quadro on your left. Follow, instead, the trails that go right and cross the rocky meadow fo Pian de Valsen. These will lead you eastwards on flat ground to the biouvac.