Dammit! I meant Arnhem Land! I should have recognized my mistake as I do know the difference between the two! Nhulunbuy and parts to the North East. I know that permits must be had from the indigenous people who own the land.
Tasmania is on our list of to-dos however, as well. I understand there's a great foodie culture there. And I like fly fishing for trout... I'll fight any tiger that tries to interfere with my fishing! Back on the mainland, I'll defer to the crocs...
Yep, Tassie is worth it for the food alone. The best quality by far of anywhere in my travels.
Not sure a winch will be that necessary where you're going especially if staying on main tracks. That's a lot of trouble and expense to go to for one trip. It could help if you get thoroughly bogged, which could be a problem depending on when you go and how late the wet season is, but it would be more something to think about if you were exploring out of the way tracks, or going to the eastern and southern ranges IMO (which can be very steep, rough and wet/slippery). I usually take the view that (within reason) for your type of travel, the closer to factory you are, the more reliable your car will be. This, along with good tyres (and an extra spare) and being as light as possible is more important for remote/outback travel IMO. If you don't need it, don't take it.
Basic off road knowledge and some care are more important. Anyway, I've been stuck plenty of times completely alone before I had a winch, it just means you've got to use some ingenuity and find other ways to get out. Winching and even recovery straps are still things I look at as dangerous and an absolute last resort anyway. The most overlooked piece of recovery equipment is a shovel.
An epirb is a must though. You can usually get them from fishing/outdoors shops for 2-3 hundred bucks. It's worth registering them online with the rescue mob, you can even send them a rough itinerary when going really remote (can be done online). This will help them know what type of car to look for, how many people etc. should a rescue be necessary.
Some places hire sat phones, for example you can hire them between Mt Dare/ Birdsville for people doing the Simpson desert at reasonable cost. Not sure about Arnhem Land though.
OSmand is a good app, another one is Guru Maps which is excellent in the free version and both have surprising amount of remote tracks. Guru maps has (or at least mine has) most of the extras free (such as elevation, contour shading etc). Whichever you get it will need to be an "offline" navigation system due to lack of mobile coverage.
As to fuel additive I suppose it could be worthwhile to stop algae, though I've found that if you really get a bad batch of fuel there is only one cure (empty/clean the tank and fuel lines). Carrying at least one extra filter amongst your spares is a good idea. In fact a good range of spares (belts, hoses, a collection of clamps and fasteners at a minimum) is a necessity.
With reptiles, they are there (although becoming less common in many places sadly) though people mostly get nipped by being unlucky enough to tread on one or purposely getting too close. They will bolt in the opposite direction if you back off and give them room. It's only when they haven't got an escape route or people get too close that they feel threatened enough to have a go. We're not on their menu and messing with humans isn't in their interests, it's not a great survival strategy.
Exceptions to this rule (which I have seen a couple of times) would be so rare as to not be worth consideration. Those species (one was a small tiger, the other a large eastern brown, but they both had stripes) aren't up that way anyway. I'm glad I encountered them in an open area, wouldn't like to have been on a narrow bush track. This is also after many decades of frequenting places they are likely to be. A lot of people doing the one trip might never encounter one.
Some basic awareness is all you need, like looking where you're treading, being careful in long grasses (especially around water sources), that sort of thing. Snakes often find a place to sun themselves of a morning and bush tracks offer a great place for this. I have learnt from experience that if there's a log across the track, never step over it without having a look first! lol.
I almost stepped on this fella recently. He was just poking his head onto the track as I was in mid stride, another half step could have been interesting. We both got a fright and did a quick u-turn. Once I settled down I took a quick snap of him. A red belly, my favourite snake.
Have seen one flatten itself out and stand up like a cobra when provoked (taking the dog for a walk which sniffed it out). Looks awesome, especially if recently shed, with the shiny black and deep red colours. It had a few strikes at the dog on that particular occasion, before I could get it back on the lead, but it didn't even have its mouth open. They're well known for bluff strikes (though I wouldn't rely on that, I know people who have been tagged), their way of saying "if it's not altogether too much trouble, could you give me some room please old chap" lol .
On one trip we stopped at a camp and luckily the wife looked before stepping out of the car, as she would have trod on a beautiful highland copperhead laying in the shortish grass. Another beautiful and docile snake, the problem being that they're not so docile when you inadvertently step on one.
No doubt you're aware about dangers of wading the creeks and rivers up that way before you cross. It's an area where "if you can't walk it don't drive it" doesn't apply the way it does further south.
With some common sense you'll have a great time and no problems at all, like the millions of others who successfully get around the place each year.
Having encountered bears in the wild in the US, I always get bemused when they worry about the wildlife in Aus. I'll take our creepy crawlies any day and at least our big cats are only in zoos, or imaginary lol.
Then again, I know people who have been on walking treks through the reserves in southern Africa. While obviously safe enough, they have more guts than I ever will lol.