Darwin and others
You've picked the best time to come up (down???) here athough the "dry" this year is a bit iffy, comes in installments.
There's a C172RG available from the flying school, the aero club is no longer in existence. They also have access to a Warrior, almost a 4 seater. Others are around but not many and it takes someone "in the know" to find out how to get them.
Don't know where CJAM got his spelling, can't recognise anywhere so I'll take a stab.
DO NOT go to Wadeye (Waadi??), it's possibly the most dangerous place for a white face in the Territory!
The Tiwi Islands have got sealed strips now, Nguiu, Pirlangimpi(Garden Point), Snake Bay ( the local name eludes me).
Top of WA, Kununurra, the Bungle bungles, Lake Argyle all good scenery. Just have to watch out if the fast kero burners are out playing chase me.
Lots more. I have no doubt there will be others wishing to tell you where to go.
Enjoy.