Missed your question about Iguazu, Mendoza, Buenos Aires being too much for two weeks. I think that is very doable with the right planning. And if you can get the One World Visit South America Pass each flight AEP-IGR, IGR-AEP and AEP-MDZ, MDZ-AEP would be U$S125 each way plus taxes etc. If not here is the link for the Aerolineas pass
http://www.aerolineas.com.ar/ar/inde...uadroTarifario
SAM