My mom and I took this trip together. She has wanted to cruise the Panama Canal and we were not interested in the typical Mexican Riviera ports, so elected the South American route hoping for something more interesting. Our onboard experience was excellent but the overall cruise experience would have been better if we had known:

Not to expect to see the South American coast as you are sailing. At sea days really are "at sea" without much to "see". That's ok for relaxing but I had thought the Andes would have been close enough & big enough for us to see mountains (somewhat like an Alaskan cruise). Nothing like this, which is ok but if you know you won't be disappointed.

Regarding the Chilean Altiplano trip: I am glad I did this and found it very interesting, but it is a very long day on the bus and we were only at the Park for about 40 minutes. Some of the scenery near the park is striking and we did see lots of animals but most of the time is mountainous desert. The trip is as described except I expected longer at the Park. I don't know whether this is typical because they don't want to keep people at high altitude for a long time, but it is a shame to go so far and have only a few minutes there. I didn't feel the bus was rushing or stops were hurried. Chilean customs: We were warned repeatedly that Chile would not allow us to bring in wood, yarn, wool, etc. There were a lot of beautiful scarves, sweaters, etc, we would have liked to buy but we were afraid they would be confiscated by Chilean Customs. They are so strict the ship warned us we could be fined up to $400 for taking even gum or mints off the ship into Chile. We had bought a Panama hat in a wooden box which the search dogs detected (I planned to declare it, but it was in checked luggage and my bag was flagged before I arrived at customs). I was required to take everything out of this very large bag while my mom waited in another room. She is always nervous being separated from me on a trip and this took quite some time while everyone in our group was waiting on us for a shore excursion. Once everything was out of the bag, the customs officer said it was fine and we were allowed to keep the hat/box. I had bought one sweater and it was apparently not a problem. Still, this experience was negative enough for me that I would suggest you do the trip in reverse order from ours. Fly to Chile and then enjoy your shopping as you cruise northbound.