Termas de Puyehue: 73km (45 miles) E of Osorno, 95km (59 miles) W of Antillanca, 93km (58 miles) W of the Argentine border
This region is home to the long-standing Termas de Puyehue spa, the Antillanca ski and summer resort at the base of the Casablanca Volcano, and one of Chile's underrated national parks, Puyehue. It is a remarkably beautiful area, with thick groves of junglelike forest, emerald lakes, picture-perfect volcano backdrops, waterfalls, and roads narrowed by overgrown, enormous ferns. You won't find a tourist-oriented town here, such as Pucón or Puerto Varas, but there are several good lodging options in the area. You'll also find a fair number of outdoor activities, scenic drives, and one of the best lookout points in Chile, which can reached by car during the summer.
The Puyehue area is best suited as a diversion for travelers on their way to Argentina. I strongly recommend this journey; it is one of my favorite excursions in Chile, and visitors can even complete a "loop" through the lake districts of Argentina and Chile by booking a one-way ticket to Bariloche via the popular "lake crossing" and later returning to Chile via bus (or tour) to Puyehue, passing first through Villa la Angostura at the Argentina-Chile border and crossing at the international pass Cardenal Antonio Samoré, or vice versa. The scenery is just breathtaking.
The road from Osorno to Puyehue is rather flat and banal, but the scenery viewed when crossing from Villa Angostura to Puyehue is stunning. Note that during the winter, chains might be required when crossing the border. The city of Osorno is considered by Chileans as one of the least attractive cities in Chile, so consider it a transportation hub only.