If you do base yourself in Santiago, there are still plenty of places to go and see and they are not that far.  We went to Valparaiso, Vina del Mar, Olmue, Los Andes and Maipo.  One thing that did concern me though in this areas north of Santiago is that fact that people farm Prickly Pear.  In Australia it is considered vermin and sent farmers broke as it took over the land.  Eventually a moth was imported whose caterpillar ate the feral cactus.  I couldn’t believe that people grow this crap to eat the fruit.  I guess this is just ignorance as I saw some of the stuff growing wild.