May find myself there in August, what are the "must do's" what are the places the tourists may not necessarily find?

Not sure I would call it a must do but there there is a local chain called Liguria, 4 spots I think, that is a good place to eat and drink.
If you ski you are going to be there at the right time and several resorts are a day trip from the City.
20driver

If you like the coast, Vinya del Mar and Renyaca are worth a visit, and for wines, the area of the Maipo Valley where there are some superb spots. All within easy reach of Santiago.

Biferia is a very good restaurant for steaks.

Valparaiso is a few hours' drive and is an interesting sight to see.