Consider using only Star Alliance carriers as you will cut down considerably on fuel surcharges etc- the 'taxes and fees' will be much, much less if you avoid AC flights.

I suggest you do some research- ie which *A airlines fly to each destination- create a spreadsheet with flights and connection possibilities, then use this information to enquire about specifc flights with the AP agent. Know when these airlines release their seats (how far in advance) as they all differ- the AP agent can give you this information.

Having said all that, a return business ticket to Buenos Aires on AC is a bargain (but you still need to pay the big $ for 'taxes and fees').

Plumber