It’s possible that I put it further out in the ocean than I should have, I’ll need to check on that. The action dropped from her queue when I tried to get her to the island directly from her home lot. My Sim had to be directed to the beach first, then I used ‘Boat Here’ to get her to the island. I did an in-game test after placing Plunder Cove in Sunset Valley: I’m sure this will work with other small islands as well.
If you rotate the lot, check for spawners that likely duplicated during rotation. You can then edit the island any way you wish. Place an empty lot in the water, at least the same size as the island, then add the copy.
Using cheats to unlock hidden islands, choose your favorite(s) and save a copy of the lot to your Library/Bin. Today I discovered that we can add the hidden islands from Isla Paradiso (Island Paradise) to other worlds.