Hi Jean,
It is a loooong plane ride for sure! We used Radisson's air and did no post or pre-cruise. They sent us from Tucson to Atlanta to Lima (Delta) and on the return BA to Dallas to Tucson (American). We tried to use FF miles and make our own arrangements but couldn't work it out. We had Delta and United miles we could have used. The problem is that Delta flys to Lima and Santiago but not BA. I can't even remember about United. Also, the return flight to US leaves around 11pm and that seems to be the norm. Because we used Radisson air package, we had a day room in BA which was nice. After leaving the ship, took the Radisson bus tour and then on to hotel where we had time to eat, shower and nap. It made the return flight much easier to take. You will love this trip!