So it is late for this update but I will do it anyway. Jamie, James, and I st out from Arequipa to Tacna by bus. As a "gringo" from the US it costs me an extra hundred to fly into Chile, but by land it is nothing. The bus ride was about 6 hours long and then from Tacna we spent over an hour in a taxi and going through customs at the border. After that we were in Arica Chile. Sadly, on Sundays everything closes including travel agencies.
We then rallied in Arica to get to the airport. After finding it relatively abandoned we pushed on and found a sales rep for Lan Airlines that got us onto the 8:15 flight to Santiago. The 2 hours plus flight beat the possible 28 hours by bus.
Being in the jetset is the only way to be. South American airlines don't charge extra for anything. Other airlines should learn from them.