My thoughts would be that where GG is, Avo's would struggle - my guess that climate wouldn't be much warmer than Hobart (correct me if I am wrong GG but you'll have pretty heavy frosts in winter yes?).
Any fruit tree will take 3-6 years to get to production, but stonefruits would do well in the area.
Other ideas:
Wine grapes
Blueberries
Strawberries
If you want low maintenance, could try
Jerusalem Artichokes (this is growing like a weed in my yard)
Yacon (trying them for first time this year)
Cheers,
The Y-man
Any fruit tree will take 3-6 years to get to production, but stonefruits would do well in the area.
Other ideas:
Wine grapes
Blueberries
Strawberries
If you want low maintenance, could try
Jerusalem Artichokes (this is growing like a weed in my yard)
Yacon (trying them for first time this year)
Cheers,
The Y-man