Get every known malaria shot you can. PNG is the worlds hot spot for malaria. I spent the day today with some Balinesse coral farmers/fish collectors. The stories they had to tell about malaria doesn't paint a pretty picture on PNG.
Check which strains it handles. Most US based DR's seem to not know that there's over 8 strains, and only inoculate for 1. Make sure it covers a broad spectrum of malaria strains. The Tawali poeple should be able to fill you in on what is up to standard
The Bali guy's I recently talked to told me horriable stories of PNG residents shaking so hard, they couldn't even see straight. The surfers I know that go there, brag about how many different strains they've had