Hi Andi,
Welcome to IIS. There was an astronomy group in Darwin within living memory so I expect that there are some local amateur astronomers who can help with specific advice (locations etc). I'm not in Darwin but eons ago I spent a few years in the tropics, including Darwin. You will be there during the end of the dry season and into the early build-up. I expect observing conditions will generally be very good but the frequency of cloud will increase and there will be some rain towards the end. There is useful information in the links below. You will see that the daily maximum will increase slightly during this period but the daily minimum increases noticeably and I expect that this is due to increased cloudiness at night.
Darwin itself obviously has all the light pollution created by 150,000 people but the light pollution map suggests that by about 20km outside Palmerston you will be in good rural skies and perhaps 50km past Palmerston you will be under Bortle 2 skies.
I don't know about the hazards posed by the local homo sapiens but do not set up near any waterbody. I wouldn't be within 100m of water lest I become dinner for a snappin' handbag. It's very very rare for crocs to take people on land but it has happened - near the water's edge. The other water-borne hazard is the mozzies and they fly further than the crocs walk. Don't take them lightly. Apart from discomfort they spread disease. I expect you will want to dress in long sleeves and trousers and perhaps use repellent - though of course be careful around optics.
I hope you like Darwin, my sister has recently returned and enjoyed herself. If you can find the time there is lots of things to do and places to visit nearby.
http://www.bom.gov.au/
http://www.bom.gov.au/climate/averag...w_014015.shtml
http://www.bom.gov.au/climate/outloo...erview/summary
https://www.cloudfreenight.com/index.html
https://www.lightpollutionmap.info/#...FFTFFFFFFFFFFF