Where can you build a mansion bungalow on Sims 2 Castaway?

On the volcano island, you can have about three in the same area. You have to build a boat first. You don't have to build the boat (Catamaran) first, I didn't. Good luck collecting all the materials w/o the cheat...it takes forever and since I already knew what I needed to do and didn't want to spend the time, I felt no guilt over using the cheat to get max materials.