Where to start??
I would have thought that if you have good cattle experience a job in the top end wouldn't be too hard to come by. Forget the phone you are wasting your time.
Sell everything you own pack up the ute and head off. I would certainly visit NAH in Catherine and Heliwork in Kununurra. When you find an operator you like and a town you like, pull up get a job and keep on to them.
The hiring in the top end will start up again soon (feb & March) and you will need to be in place ready to start at a moments notice(or less). The guys on the spot get the jobs thats why you need to pick the company. If you are not around when they need you they will get somebody that is.
If you want to chase cattle obviously its all r22. If you are going to have a crack at top end tourist work don't bother talking to anyone until youv'e got that 47 endorsement.
Good Luck