The Italians describe this trail as "mulattiera", which translates literally as "mule's earth" but perhaps more correctly as a mulepath. These are typically old roads predating cars that are just wide enough for a wagon to pass. And apparently mules can pull a wagon up anything because at times they are crazy steep!
The trail surface changes from earth to cobblestone, to gravel and back, with particularly steep segments armored in asphalt or concrete. In any case, they make for good mountain biking routes.
This mulattiera starts at the Parco Alpe del Vicere (where there is parking) at the top of via Partigiana (Partisan Way).
From there you'll climb. After about two miles, you'll reach the rifugio Mara (mountain hut) and your first chance to enjoy a refreshment at the Bocchetta di Lemma (Lemma Gap) between Monte Croce and Monte Bolettone. Looking back from the rifugio, you'll have a great view of the foothills to the south towards Milano.
This brings you to Dorsale del Triangolo Lario (Crest of the Lario Triangle Peninsula)
at the intersection with DTL: Sentiero dei Faggi (Trail of the Beech Trees)
. The dorsale roughly follows the highest peaks in the area, although frequently it passes just below the actual peaks. Nevertheless, the panoramic views available from this route of Lago di Como (Lake) and the surrounding alps are stunning.
Another 1.5 miles of climbing takes you to the rifugio Riella in the shadow of Monte Palanzone. This is another good place to stop for a refreshment as their outdoor patio acts as a balcony over Lago di Como with the Alps defining the Italian-Swiss border in the background. The rifigio Riella also signals that the majority of the difficult, sustained climbing is over.
The mulattiera then continues for about 1.5 miles in a relatively flat section at about 1300 m (4300 ft) elevation. After that, the trail continues steeply downhill (200 m, 600 ft in 0.8 miles) before ending at the Rifugio Colma del Piano at Strada Provincial (Provincial Road) SP44. Here you can continue to follow the dorsale with DTL: Monte San Primo
if you wish.