By the way, if anyone is thinking of going there, whether during Lisa's Fitness Week
or another time: LAN Airlines (Chile's home airline) just started flying to Santiago non-stop from both LA and NYC
. Which means you can probably get good 1-stop connections from anywhere in the US on their partner American. LAN is in the same oneworld airline alliance as American, so you could earn AAdvantage miles or possibly use AAdvantage miles to get there. It looks like LAN has some good introductory fares on this route. LAN also has connections through Lima Peru.
Also Delta has nonstop service from Atlanta to Santiago. Good if you like to earn Delta, Northwest, or Continental miles (all partners in SkyTeam.) Also there are some Aeromexico routings via Mexico City which would earn miles in any of the SkyTeam airline programs.
If you plan on earning United, Air Canada, or US Airways miles (all partners in Star Alliance), options are not so good ever since Varig went bankrupt and was thrown out of Star. No cheap *A flights to South America anymore. Air Canada has good 1-stop routing through Toronto (and that's a great airport for international connections including from the US - I just transited it last week to/from London and it was less hassle than Chicago O'Hare or Washington Dulles). However the cheapest Star Alliance routings are about $1200 US
Fares seem to be well under $1000 USD which is cheap for deep South America from the USA. Not cheap in an overall sense, but not bad. I'm seeing coach fares on Delta from NYC via Atlanta for $645 all-in (with taxes and fees) on Orbitz, which is darn good. I used the dates around LM's week with a couple of days on either side (e.g. 8/22-9/4) for this fare check. The LAN nonstop is $720 all-in. Similar prices when I checked a few weeks earlier in August. Plugging in Denver as the origin, fare only went up to $897 on LAN or $903 on American or Delta 1-stops.
This is dirt cheap for those dates - when Lisa and I first planned to go and looked at fares last December for this August, the cheapest fares in coach were about $1200. We ended up using United miles for a round-about routing via Buenos Aires down and Sao Paolo back up, instead. Looks like LAN adding the non-stops created enough competition to force some of the other airlines to drop prices.
Keep in mind you do have to go to Portillo for a Saturday-to-Saturday week - there's no day-by-day lodging. Given possible road issues from Santiago and doing some sightseeing anyway, you probably want to fly down no later than Wed US departure (Thurs arrival in Santiago) and plan to fly out no earlier than Monday following your ski week.