I'd be up for a flight, but there aren't that many on the day I arrive and I'm carrying more and heavier luggage than the most expensive fare allows.
The overnight bus will take me all the way to La Falda, so I don't have to have family drive into to the city to pick me up. I'm guessing even with getting a hotel for a day the cost will be around 20% of the least expensive flight option.
Changed up my plan so that I'm going to get a hotel for the day, rest up after a red-eye flight/customs/migraciónes/etc, shower, seek out a good pizza (I'm a NYC pizza snob and the options I've lived with for the past 9 years in Perú are meh at best) and take a cab to Retiro to arrive at the recommended time before the bus leaves, minimizing my time at the airport and Retiro.
But I'll look into Terminal Panamericana as well. Using a few of the bus websites I haven't come across anything from that terminal going to La Falda, but I've got a month to figure it all out so I'll investigate. Thanks for the suggestion.