Do you have any idea what kind of lighthouse you want to make?
As I assume, it could be some kind of abstract lighthouse or even some specific lighthouse. Usually a lighthouse is presented as a high round tower and a house near it. You can sharpen a tower piece of four pieces of wood that you put together. Each piece must go down the neck of the bottle. You can make a simulation of the masonry and then it will be easier to hide the joints of the lighthouse details.
I think you can even insert an LED, a battery and a control unit into it.