Not a very tidy post but I'm in a hurry today. Here are some ideas for Mendoza and Santiago regions.

mendoza:

Here's a list of some things to do in and around Mendoza. There's a hike that looks interesting if people are interested "Hike up Cerro Arco" about half way down the list.

http://spanishinmendozaargentina.greenash.net.au/mendoza/

some sleeping options:

http://www.homeaway.com/vacation-rental/p448946#calendar

http://www.vacationrentals.com/vacation-rentals/105012.html?promoType=none

http://www.venere.com/hotels/mendoza/apart-hotel-mendoza/?sd=08&sm=11&sy=2012&ed=11&em=11&ey=2012&pval=4&rval=1

http://www.venere.com/hotels/mendoza/hotel-cordon-del-plata/?sd=08&sm=11&sy=2012&ed=11&em=11&ey=2012&pval=4&rval=1

http://www.venere.com/vacation-rentals/mendoza/vacation-rental-soltigua-apart/?sd=08&sm=11&sy=2012&ed=11&em=11&ey=2012&pval=4&rval=1#reviews

santiago

free (tips) walking tour: http://spicychile.cl/

some other day/short hikes: http://www.santiagomagazine.cl/living/0096-gateway-andes-5-great-hikes-around-santiago

some other ideas from TripAdvisor: http://www.tripadvisor.com/ShowTopic-g294305-i2020-k4873495-Chile_Itinerary-Santiago_Santiago_Metropolitan_Region.html

some sleeping options:

http://www.tripadvisor.com/VacationRentalReview-g294305-d2022013-Fully_Furnished_Apartment_in_Santiago_Centro-Santiago_Santiago_Metropolitan_Region.html#amenities

Enjoy your weekends