From Vagli Sotto (600m) the route climbs to the town of Vagli Sopra and from here, following the old mule track (trail marker 177), it climbs up to Campocatino (1000m). Following the same marker 177, the path climbs around Monte Roccandagia on its western side, towards the Tombaccia Pass.
The landscape has a sudden change; arid and lunar, now, it shows one of the most characteristic and imposing aspects of the surface karst phenomenon in the Apuan Alps. The sinkholes of Carcaraia are undulating depressions that must be treated with some caution. Having reached Focolaccia Pass, the encounter with the most relevant economic activity of the Apuan Alps can be shocking. The marble quarries have carved the watershed of the chain, the perched roads and the ravaneti open white wounds on the sides of the mountain. You must pay close attention to the signs that are often removed from the excavation activity.
Then turn left going up the ridge along path 148 which in a short time leads to the top of Monte Tambura (1895 meters).
Enjoying the panorama from the top, continue towards SE to the Tambura Pass, where you cross the ancient Via Vandelli (trail marker 35).
Turning left you descend the Garfagnana side and upon reaching a quarry continue to the right along path 35, from where you soon meet the GT path which leads to the Arnetola and Vagli Sopra valley.
Once you get down to the quarry it is also possible to reach Vagli Sopra, turn left following path 147. After a very short equipped section, with about an hour and a half walk you reach Campocatino, from where turning right keeping path 177 you it goes down towards Vagli Sopra.