He is definitely against the TPP - but of course that's a different thing. Plenty of Australians aren't too fond of it either.
I hope you are correct and they are just extrapolations that even hardened Australian Trump supporters have mentioned in posts.
There's some reflection on his policies here, including:
However, it is in the strategic realm that a Trump presidency would most concern Australia. Trump has called upon Japan and South Korea to contribute more towards the cost of stationing American military units in their countries (both of which already make substantial financial contributions to defray US expenses). Declaring that America can’t afford to defend countries like Japan anymore—and ignoring the considerable benefits America accrues from its military presence in allied countries—Trump has suggested that South Korea and Japan should consider developing their own nuclear arsenals and that he would be open to withdrawing US forces from those countries if they do not further subsidise the US military presence.
As figures such as Australia’s former ambassador to the US, Kim Beazley, have pointed out, such policies could undermine Australia’s security. If a Trump administration did encourage South Korea and Japan—two American allies with a troubled history and dislike of each other—to acquire nuclear weapons, it may prompt other states in the region to acquire them. A growing number of nuclear-armed states in a region characterised by unsettled territorial disputes, an abundance of nationalism and historical grievances would make Asia a more dangerous place—an outcome clearly inimical to Australia’s interests.
