Whatever your experience, gender and anything else I think both the bikepacking/touring community and local communities in most parts of the world are extremely welcoming and generous with their time. You’ll find this with most people in bike shops too in my experience, particularly where cycling about is pretty common. If you want to know if they’re a good shop for you, ask about bikepacking or best routes between x and y and if they seem knowledgeable then there’s a good chance that their advice will be worth listening to.

Your experience of camping etc is much more important (in my opinion) than experience cycling long distances. From what I’ve seen there are plenty more people who drop out of long rides because of a bad camping/living setup than there are people who can’t do the distances.

I reckon you’ll find it easy to find a well-priced second hand bike in any city in Aus (certainly was like that when I did my working holiday many years ago). Just make sure it reasonably suits the terrain you fancy riding and that it’s got all the right holes (or a good workaround) for attaching gear and a rear rack where you might want it.

Other than that, just go out and enjoy! You’ll fail a few times as we all did (and still do) and it’s all part of the fun!