Originally Posted by ALadyNCal
My suggestion to them has been to fly LAX-EZE, enjoy EZE for a few days and then take a bus (or similar) to SCL and save the $100.
BTW, her U.S. passport is not 'newly acquired'. I believe she became a citizen as a youth -- 10+ years ago.
Thanks 
A bus from EZE-SCL?
I hope they have time and the weather is decent. I hope that this is not just to try to save $100 per person on the visa fee.
I certainly do recommend a visit to EZE -- with no visa fee -- but I don't know if I'd necessarily recommend taking a bus from Buenos Aires to Santiago. (The airfares aren't that bad.)
If they happen to do a land crossing between Argentina and Chile, there is no guarantee that a passport check won't occur and that a reciprocity entry fee won't be collected. Many Americans visiting Chile on a longer-term basis go by bus or car and use the Chile-Argentine landcrossings to exit/re-enter in order to get stamped such that they are not seen as overstaying. I do not know if they have to search out a Chilean and Argentine immigration official or not, but I'd be surprised if the main routes don't have at least some immigration control presence.