What can you do with the wuhu island vacation home in wii sports resort

As far as I'm aware, not much. Nothing happens outside of Island Flyover, and the only thing that happens in that activity is that you can see a house on Private Island with a flagpole with your Mii's face on it. The text to the i-point there also changes to say that your Mii's house is located here. There are also a few Miis with balloons near the house (they don't appear before it's built), they may be your other Miis; it's hard to get close enough to see their faces, but I guess it's implied they're your visitors. However, you cannot land your plane there (you just crash if you try), and thus, you can't get out and/or enter the house. Also, I believe the Private Island i-point text doesn't change depending on the time of day, whether or not your house has been built there.