You have to camp out.
Ain’t that why you are travelling this way in any case. Those fantastic sunsets and clear night skies with stars in a dome from horizon to horizon.
Unlike Texas, say, the attitude to camping in rural Australia is usually relaxed. Take some minor precautions and it is remarkably safe: get some distance off any road with traffic, be discrete with the campsite. The Australian landscape is hugely under populated. No one will disturb you even if they can see you as they race to their own destination.
The distances between some roadhouses are so large they require a few days travel: the only road house, Rabbit Flat, in the 583km from Yuendumu to Billiluna has now permanently closed. Halls Creek to Kalkarindji is 407km with no house or shop, and scarcely a car to be seen in between.
Once you accomplish one of those legs you realise that you don’t need to pay over money for the privilege of sleep.
Some technique may need to be evolved. Like camping 20km from a town to avoid meeting any semi wild town dogs, then spend time during the day in town, getting the groceries, catching up on emails at the library, a shower at the local roadhouse, having a cheap and regrettable Chinese meal, etc, and then heading out of town when it’s mission accomplished.
Camping out in Australia is one of the magnificent delights of travel.