Princess runs 2 cruises out of B.A., Argentina. Starts and ends at same port. Does a cruiseby Antarctica. It goes on sale next month or so for $899, or did during better economic times.
Some drawbacks for me of flying in and out of two airports. Well, Chile for one charges a $100 or more Visa. If something goes wrong, I might imagine higher flight change costs. And the biggest reason is...I want to spend extra time at each place, so a 5 or 6 week trip ends up being 8 weeks.
But, aside from the above, I might be interested if the cruise is cheap enough.