To the south of Tucumán, Parque Nacional Campo de los Alisos is a tempting destination, particularly if you have your own transportation. A hilly park at the zone where the montane forest and cloud forest meets the Andes proper, it offers good walking and climbing. There's free camping and a climbers' refugio (shelter). The park entrance is 12km beyond Alpachiri, reachable by bus from Tucumán. The park office in Concepción, 18km before Alpachiri, might be able to help with transportation.