Salta/Jujuy is my favorite place in Argentina. I´ve been 4 times, and would recommend looking into Movitrack
http://www.movitrack.com.ar/index_ing.html for tours, even if you just do one and then rent a car to see the rest - it is an experience like no other! They have an excursion that does the route "a las nubes", but in the special Movitrack vehicle, which allows you to pop your head out the top (each seat has its own little roof "door") and feel the mountain air and get magnificent views and pictures.
Also, I have stayed at this B&B 3 times...Silke and Riccardo are fantastic! It´s called Carpe Diem, and it is located in Salta city.
http://www.bedandbreakfastsalta.com/bed-and-breakfast-salta-home-ing.htm
The one thing that I would say is an absolutle must is to see the "niños del Lluaillaco", which are 3 almost perfectly preserved mummies that are on a rotating display at the MAAM museum (
http://maam.culturasalta.gov.ar/) - it´s located right on the central plaza in Salta city. They are truly amazing how well preserved they are.
Aside from that, Cafayate is a great little town and has a phenomenal empanada place - La casa de las empanadas. I would just ask someone near the plaza where it is. Hands down the best empandadas I have ever had!
Oh, and I recommend trying llama while you are there. I believe I ate it in Maimara and Cafayate. It´s fairly common on menus up there. If you can find it prepared with a little garlic, parsley and olive oil, mejor!!!