Hi,
If you take the rv to Oz, simply replace the converter with one that accepts 240 volts.
btw mostly there are Americans on the forum--so they have no idea what 30C means. They will understand 86 F.
Do you have a planned route? Are you coming in the North American summer?
RV's have a lot of glass, which is nice, except it means there is a lot of solar gain. I live in the prairie part of Canada. We do get up to 41 C here most years. Mesa Arizona gets to 45 C pretty much every year and sometimes to 50 C
Again temperatures really do depend on where you want to go.