Can you fly Japan Airlines (JAL)? I think that they would be your best bet. JAL flies from HND to OKA. If you have to fly into Narita then I would check the price of a train ticket to HND. Also If you fly through HNL like you said you might, JAL flies to HND thereby negating the train. Their website is jal.com. And if you search the routing on their website you will get other options as well.

I would do some more research. Also you can go to airlineroutemaps.com which will give you a better idea of who flies where. Also remember that as a nonrev we often take two steps backward to take one forward.

Good luck and let us know how it goes.