Great report and pics. Makes me want to go back again.
I also did a trip to Sydney and Melbourne back Nov 2013, but did the tour van thing for the Great Ocean Road and the penguins. It's great you were able to take your time and see more things than us tour bus folks.
I had a friend who used to do a the caravan thing on long weekends up in the Redding area in NorCal. It was a lot like your mum's that it expands out - just no washer.
Looking forward to the rest of your trip report.