If you take the rig home, besides having to change all your 120V electric and electronics over to 240 volts you will also have the entry and patio awning on the wrong side as well as water, sewer and electric connection points.
One possibility would to fit a good high power inverter or two say a couple of 2,000 watt pure sine wave inverters to run everything. Then all you would have to change out in Australia would be the battery chargers for 240V input. You would need good battery capacity though, at least 4, better 6 of the 6V golfcart type battery or the equivalent capacity in 12V batteries. If you were to go that route a large solar array would be worth considering (500-1000 watts). But: You still have the problem of everything being set up for the wrong side of the road. In pull through sites you could just drive in the wrong way but back ins would be awkward.
In your shoes I would seriously consider buying a unit and selling it before returning. AND that would be a used rig. New rigs ARE NOT ALWAYS TROUBLE FREE and you would not lose so much on depreciation.