Ushuaia (last city on the South American Continent) for a day or two (best sea food on earth) then over to El Calefate for the Patagonia boat ride around the glaciers, icebergs and local food/sites (2 days). If your schedule permits, buzz up to Iguasu National Park and see the falls and maybe a panther or two in the jungle (great tourist hotel) 1 day. Back to Buenos Aires and spend maybe 3 days with the sights (PM me for details or google is your friend). Flight to BA is overnight from DFW or, MIA. Spent 19 years back and forth but my employer was paying the bills. Great places to visit! John