Argentina Travel?

This summer I am going to travel to Argentina to cap off my senior year and to visit my family. The last time I went I was 2 years old so dont remember much. The trip is gonna be from June 27th till august 28th cause the 30th I have to report to college. Anyways these are the places I will visit and can anyone tell me about them and whats to do.
Buenos Aires (Of Course)
San Juan (Where my family is from)
Mar de Plata
Cordoba
Mendoza
Tucuman
Bahia Blanca (To visit my Uncle)
Salta
Santiago del Estero

I only know that there is going to be winter in Argentina so you should visit the south (Patagonia) so you have a chance to see snow. Either way, bring along a thick jacket.