I've just booked myself on this tour starting from Darwin! anyone else going? got any tips?

Seeing as I live in Darwin I thought I should give some advice!
I'm guessing you're going middle of the year some time, cause if you are then you'll need both clothes for warm and cold temperatures. Darwin, Katherine and probably even Tennant Creek you shouldn't need much more than shorts & t-shirts but any further down in the Northern Teritory, you will. The temp during the day is quite warm but it will get very cold at night cause you'll be in the middle of nowhere!
If you are looking for somewhere to stay in Darwin, find a hostel on Mitchell Street in the city - big backpackers scene.
Other than that, have fun!!