Mendoza is Malbec country, and plenty of vineyards double as places to stay! About a 2-hour flight from Buenos Aires, we recommend exploring Uco Valley or Lujan de Cuyo. There is also amazing hiking, horseback riding, and adventure sports in Mendoza.
After Buenos Aires, this is our favorite city in Argentina! Very Swiss Alps-like, with a ton of hiking, lakes, and mountain views. Try the Refugio Frey hike if you like a challenge, or the Cerro Llao Llao for something more chill. The Centro Civico (downtown) has great restaurants and artisanal shops. Stop by Mamuschka for chocolate, Patagonia for beers, and of course, Rapanui for ice cream! You can also rent a car and do the classic Circuito Chico drive around the many lakes, or extend your road trip. More on that below :)
Rent a car and drive this stretch of Ruta 40 between Villa La Angostura and San Martín de los Andes, which takes you to 7 (duh!) different lakes, and many hikes along the way. Plan for a full day of driving so you can really savor each stop. There are many places (and sandwiches de miga) to enjoy along the way :) Most people drive it from Bariloche, about 1.5 hours to Villa La Angostura and another 2-3 hours to San Martín de los Andes with stops. You could also do it as a one-way trip!