Bariloche looks like a place somebody planned, and somebody did. The town grew from a shop called La Alemana that Carlos Wiederhold opened in 1895 to supply settlers who mostly traded with Chile, and it stayed tied to Chile until the railway arrived in 1934. Then the national parks service, under Ezequiel Bustillo, hired his brother, the architect Alejandro Bustillo, to give the place an Alpine face: stone and larch-shingle buildings, a Civic Center that opened in 1940, the Llao Llao Hotel on its peninsula. The "Little Switzerland" look is a 1930s design, and it still works because the real thing behind it is genuine: Lake Nahuel Huapi, forests, and peaks that keep snow into summer.
This guide is written for the warm season, November to March, when the lake is cold but the days are long and the trails are open. It is a nature trip with a town attached, not the other way round. You'll ride chairlifts up to lake views, take a boat to an island and a forest of orange-barked trees, spend a long day at the foot of Tronador and its black glacier, and hike to a mountain refuge. In between you'll eat well. Bariloche is Argentina's chocolate town and has more craft breweries than a town this size should. Five days is the right length because the best things here are scattered over 20-60 km and half of them depend on weather and boat times. The ski season gets its own honest section on day five, because Cerro Catedral is the other reason the town exists.
The plan runs day by day: the town, Cerro Otto and chocolate on day one, the Circuito Chico on day two, Isla Victoria and the Arrayanes forest on day three, the Tronador day trip on day four, and Cerro Catedral and the Refugio Frey hike on day five. Start on a Tuesday: the Museo de la Patagonia is closed on Mondays, the Catedral lifts are closed on Sundays, and this order puts the Frey hike on a Saturday. Prices are in US dollars first, because pesos go stale within weeks (see the money tip). For the country as a whole, see Argentina.