Perhaps if you just shuttled between Redfern and Erskineville. You’d have to get out every now and then as there’s no toilet on those trains.Couldn't do this in Australia, rents here are unsustainably high but that's nothing compared to the cost of our interstate rail - $3000 for a 4 day trip, Sydney to Perth.
https://www.greattrains.com.au/indian-pacific/sydney-to-perth