If you can access Tortimer's Island via Kap'n, just go on a diving or fish catching tour and grab some coconuts/bananas on the tour that you can plant in your town's beaches. It doesn't cost anything to take extra tours while you're already on the island, so you could take as many as it took until you found all the fruit (labyrinth is the only one that won't let you keep the fruit you fill your pockets with)