At the west end of Lago Todos los Santos, the source of its namesake river, Sector Petrohué is most popular as the port for the passenger ferry to Peulla [1], which leaves in midmorning and returns in early afternoon. Turismo Peulla, which operates the Peulla ferry, also runs a daily excursion to Isla Margarita, an island that rears its head above the middle of the lake, in January and February only.
Since most of Sector Petrohué lacks an integrated trail network, visiting remote areas requires either hiring a private launch or contracting an activities-oriented tour, but there are a few easily accessible options.
From Playa Larga, the black-sand beach north of Hotel Petrohué, the five-kilometer Sendero Rincón del Osorno follows the lake’s western shore. Six kilometers southwest of Petrohué, on the south side of the highway, Conaf charges US$2.40 admission for the Sendero Saltos del Petrohué, a short riverbank trail that follows a series of basalt bedrock rapids and falls too rough for rafting or kayaking. Below the falls, Puerto Varas [2] operators start their Class III–IV descents of the Río Petrohué (around US$45), which is suitable for novice rafters but interesting enough for those with more experience. Sites suitable for rock climbing are nearby.
Links:
[1] http://www.moon.com/destinations/chile/sur-chico/puerto-varas/sights/parque-nacional-vicente-perez-rosales/sector-peulla
[2] http://www.moon.com/destinations/chile/sur-chico/puerto-varas