*note: everything has to be at-least LOOSELY related to canon.
e.g. of ^: since the fate/well-being of Australia is not clearly defined in canon, I had fun in making up details ^_^ , but stuck to the lore as there is no evidence to suggest that other countries did not have vaults and hell, if they have laser rifles/pistols/shotguns, who says someone didn't find a way to consume geothermal energy.
**note: do not completely disregard canon.
Australia, Melbourne.
Watching propaganda on TV writing down how many inconsistencies there were, what they were and how full of crap the poly was, in the Vault that I designed when I was 23 while my wife is watching her soap and the kids are studying algebra, not realizing that in contrast to their later years is child's play. The vault would have a hydroponics lab for growing vegetables, fruit and for making the air fresher than just an air purifier/recycler, a gym for keeping fit while staying alive from the presumably dangerous and toxic exterior (from our proximity to a major city) (the equipment i.e. treadmills generated some power and the rest was derived from solar panels that would routinely reveal themselves at intervals during the day and slight amounts of geothermal energy being extracted) and a separate habitat (which was extremely hard to build and coax grass to grow) in which 5 cows would reside providing us with milk, and when necessary, meat.
Either that or I would be enlisted in the elite of Australia's armed forces and be assigned to a top secret vault that has the core mission of securing key areas within Australia once radiation has safely dispersed, allowing resettlement of our great country by the greatest minds, the most earnest citizens and the most hardy soldiers (and their immediate families) of Australia.
And I suggest, have fun with creating your story, just keep it reasonable, for example :facepalm: no zombies/aliens please -__-