If you live in Hauula, you most likely know the owner already. The first thing you want to do is get financing. Once you have that, then it doesn't matter to the seller if you use a mortgage or pay cash, as long as the sale is completed. You also need to check on insurance before you build anything, so check that before buying.
If you plan to build a home on that land, there are several things you need to. Try to find someone else that built a home in the area recently. They can get you going in the right direction.
Call me you have any questions.
I would have someone do some research on the property for you to check a few things before contacting the owner. You may want to find out; what some comparable properties are selling for, who is on the title, are you planning on paying cash or get a mortgage. With this type of a situation you want to make sure that you offer the owner something that is going to make it worth their while, because if its not for sale they most likely don't need to sell it.
I would be more than happy to help you get some further informatin for you and answer any of your questions in more detail. Please feel free to contact me.
Chris M.T. Bodden