I hope you have a sense of adventure, along with plenty of common sense.
PNG flying is not to be taken lightly.
Avgas is a real issue, and the best people to talk to are Pacific Energy
Aviation on +675 325 5520. Even MAF have great difficulty getting the stuff, and they are about the only operator left with a substantial piston fleet. Everyone else has gone turbine. It is also highly unlikely that MAF would sell you any, as they go to considerable trouble to get the stuff.
Accommodation is available in most centres, but expect to pay at least double the rate for an equivalent stay in Australia. Google will help you a lot here.
As for scenery, it is truly spectacular (Moresby excepted), with mountains, beaches, islands, waterfalls; whatever you want.
Get some good background info on the places you plan to fly, including talking with local pilots who have been to those places recently. It is very, very different to Australia. Lots of planning will be required.
Good luck, and enjoy the trip.