Hi
Good idea to go to that area as weather will be better than in south. Have you thought about taking a tour, can ease some of the stresses of planning. Lots of operators have tours in the Salta area. With two weeks you can take a wider tour too, perhaps including Cordoba, and Buenos Aires or Iguaau falls. Here are a few operators, you can get some ideas by taking a look at itineraries.

Argentina Discover have a seven day Classic Northwest Argentina tour. Latour, an experienced and more upscale operator, also have short tours in the Northwest. They also have a package in Iguassu which you might be able to combine with a Northwest package and then to Buenos Aires. Kontiki Tours specialize in Latin American Travel. They have a seven day Buenos Aires and Iguassu tour.

Hope this helps