Bring a bathing suit. The beaches are very nice. Also, be ready to tour many of the pineapple plantations. Most of the attractions require a four wheel drive vehicle to access. Four Seasons manages a resort on this island. Have fun on your trip! wish I was going as well!
Since Lanai is a tropical destination, I would take advantage of the opportunities that are unique to the location. I recommend walking around to see how people live there, and finding a nice place to swim.
