This trail is best accessed from Como using the Funicolare Brunate (Mountain Cable Car), which whisks you up nearly 500 m (1650 ft) in about 10 minutes, the alternative being to climb some very steep roads from the level of Lago di Como (Lake).
The funicolare deposits you in the central plaza of the small town of Brunate. From Brunate, a narrow, paved road leads you to the village of San Maurizio. If you can find a way to secure your bike(s) in San Maurizio, a short walk takes you to the Faro Voltiano, a 29 m (100 ft) lighthouse which offers panoramic views of Lago di Como and the Alps to the north.
From San Maurizio, continue climbing and shortly thereafter the pavement gives way to the gravelly rockiness of a typical Italian mulattiera (literally Mule's earth, but more correctly a mule path). This continues the climb following the ridgeline past several Baite (chalets), some of which offer refreshments in the summer. With the passing of each Baita, the mulattiera becomes more and more rough and there are a couple of sections that are particularly steep.
At around 3.5 miles, you'll reach a final Baita (Baita Boletto) and just beyond that the mulattiera forks into two singletracks: DTL: Sentiero dei Faggi (Trail of the Beech Trees)
and Monte Boletto Sud (Monte Boletto South)
There is a fainter, very steep singletrack that goes directly up to the summit of Monte Boletto, but I suppose this would be a difficult trek for most riders especially considering that you'll have already climbed 450 m (1500 ft) to reach this point from the Funiculare Brunate.