Anytime is a good time - if you book off peak season or last minute you can sometimes get really good deals. Book it so that it is optional for you, we are pretty flexible generally. Around new year and into March is hot (outback will be hell) - so if you want to get out there, from now until late November (or late March/April) is better. We have spare room and bed (Ikea bunkbed, lol), so you will have reasonable privacy, except the cats will probably want to sleep on your head.