Try and make an itin that would arrive from MVD and depart from EZE/AEP.

That way you could avoid the Visa Reciprocity fee as long as you get into Buenos Aries via any form of transport aside from Air. A ferry looks to be about $40 CAD

You could book an open jaw for your transcontinental flight, and then connect them.

YVR-SAO-MVD // EZE-RIO-YVR

If you do that, then all you would need to pay for in addition to your intercontinental flight would be SAO-MVD and EZE-RIO.

If you have miles any spare miles, you might be able to redeem for 2 oneway South American Flights. on TAM or LAN?