We are a retired couple planning our first trip to Argentina and Chile for 16 nights Feb 28 - Mar 15. We prefer to rent a car when practical and feasible - if roads and maps are good! We are saving the Falls for a trip to Brazil in the future. How does this itinerary sound?
4 nights BA
Fly/bus to Cordoba - stay 3 nights
Fly to Bariloche - stay 3 nights
Lake crossing to Chile - stay Puerto ?
Rent car and drive to Santiago - stopping 2 nights on the way- ? (Concepcion?)
3 nights in Santiago or Valparaiso
Comments? Suggestions? Thanks. SWR

Sounds like a good plan, after the lake crossing stay in Puerto Varas one night, much more charming than Puerto Montt, which is just a big city.

Drove in Bariloche, no problem, did not drive in Chile, but roads were good.

Sounds like a nice trip.

After Puerto Varas, drive north choosing a detour to one of the other lakes. The easiest would be to go to Villarica and/or Pucon. You have to head back to the highway again, but the main highway is excellent. Or head toward the Termas de Puyehue from Osorno. Concepción is just a large city and, although very nice, won't offer much for a tourist.
Perhaps the second night, stop in Santa Cruz in the Colchagua valley for some wine tasting.

Would agree that Concepcion doesn't offer much exciting for tourist. While it has been a few years since I was there, it was obvious the city was not used to English speaking tourists. I have limited Spanish and got along fine in Santiago, Vina Del Mar, Valparaiso, BA, and Salta region.
It seems you do not plan to drive in BA which is great idea. Taxis are cheap, and the traffic is beyond description. You will enjoy Chile and Argentina!

Specially SAlta region! You will fall in love!
As collegemum, skatedancer, nicci, and mjs and many others who visited the area, drink our wines and ate our empanadas!
Wamr regards.
F.