I have the barren banks with the castaways in my studio ready to be downloaded and placed in your world .... I usually like to add them after completing challenge 2, simply bull doze and change the lot to residential and place the new lot OR ...add your own sims after changing the lot to residential for the challenge.
Here is the link:
http://www.thesims3.com/assetDetail.html?assetId=6997254
I uploaded it to my studio so those who wanted to, could do the challenge and use any world they wanted.
... I'm gonna need to add the Tuzu tomb to my studios too, for those using other worlds!
Good luck with the challenge I hope you are having fun with it!
