Looks like TACA Peru has only two routes at present, LIM-IQT (Iquitos) and LIM-CUZ (Cuzco). In both cases, the plane originates in LIM reaches its destination and does an immediate turnaround, so you can be back in LIM in about 3 hours. Looks like both routes are in the area of $200 r/t.
As for Jaguar's question regarding hotels, I would interpret the rules as requiring three nights with two different hotel partners (total of six nights), based on the fact that the 500,000 miles uunquestionably requires three nights, and one would expect a larger night requirement to earn the $1,000,000 miles.
I still can't believe that I'm really serious about doing this, but I think I am.