Budget is the biggest restrainer in these trips, the next is the group of airlines you choose in which to make the trip. This last option is usually decided by where you wish to visit and becomes a compromise of cost, essential visiting places and non essential places. We had had a taste of South America by going to Peru so we wished to see more, this meant that we had to either travel up and down the Americas or to get across the Pacific by another route. We didn't want to travel via USA because of immigration controls where you lose half a day due to no 'in transit' facilities so we are booked out of Chile to New Zealand. This has opened up other areas in the South Pacific for us to visit like Easter Island and Tahiti. We wanted to see Brazil but we are with the wrong airline group so we start by flying to Buenos Aires on 6th Dec.