The ultimate origin of the Wild Southwest can be traced back to two things - an ABC TV show and a childrens' picture book - both dating from when I was in primary school (that's elementary school for our American friends) in the mid 1980s.
The TV show was an episode of the Australian Broadcasting Corporation's Winners series named Quest Beyond Time. This particular episode told the story of a young man from contemporary Sydney who gets pulled through a time warp to a post-apocalyptic future where he has to undertake a quest to save a tribe from a deadly plague. It featured most of the cliches of post-apocalyptic fiction, but with a particularly Australian flavour and some genuine though behind it. The novelisation of the episode (by Tony Morphett) was even better, portraying a detailed and varied society that felt like it could really work - rather than being a bunch of barbarians running around a desert, which was fairly standard post-nuclear fare at the time.
The childrens' picture book was Henry's Quest by Graham Oakley. Set in a post-industrial (although probably not post-nuclear) England, it takes the reader on a brilliantly illustrated journey through a society living in the overgrown ruins of the 20th century (an excellent review with pictures can be found here).
I read both these books over and over again as a kid, and they obviously warped my thinking in a serious way because I've had a fascination with post-apocalyptic societies ever since.
My first attempt at constructing a post apocalyptic society was a lengthy story I wrote in high school in the early 90s. Titled The Quest of the Xavian Chief it was set in Perth, maybe 200 years after a nuclear war. Society had reverted to tribalism, and the title character (inspired by the ravings of an elderly, pot-smoking shaman) set off on a quest to contact a surviving technological society on the far side of the Darling Range and obtain from them a cure for the plague ravishing his people. It was completely derivative of both the works above, but nonetheless managed to make it into the finals of a local writing contest. A few years later I started a major revision, trying to give it a more realistic and mature plot. This effort ran out of steam fairly quickly, although I at least managed to transform the people over the hills from a bunch of eco-happy hippies into militaristic fascists.
In high school I also encountered the works of John Christopher and was particularly influenced by the depiction of a ruined Paris in The White Mountains and the depopulated Britain of Empty World, which showed me that you could have an apocalypse without nuclear weapons - although my fondness for the bomb as narrative fuel remained.
Over the succeeding years I made a few more attempts at post-apocalyptic works - mostly Civilisation II scenarios that never got finished. Then in 1997 Interplay released the computer game Fallout...
I went Fallout nuts. I played the game through about five times in a row, and got involved with a number of online fan sites, particularly No Mutants Allowed. Here I perpetrated the ultimate fanboy sin, and wrote fanfic (I know, I still feel dirty ten years later). My Fallout obsession continued with the release of Fallout 2 in 1998, but more or less came to an end at the start of 2000 when I got a job building websites and no longer had time to sit around all day posting on forums and playing computer games.
Prior to this point however I'd started work on a particular fanfic. One set in the Fallout universe, but in the southwest of Western Australia. It never got much further than about five paragraphs and a vague plot outline, but those few paragraphs included a lot of information and ideas. Albany as the major city of the region for instance, and ring pulls as currency (rather than Fallout's bottle caps). There were mutated cattle named 'aurochs' - which unlike Fallout's 'brahmin' only had one head - and a colder climate with sleet and snow. There was even mention of the Mount Clarance radar station, the Porongurup Rangers, the STS Leeuwin and the Governor Stirling Hotel.
Although this story never came close to completion, it remained in the back of my head.
A few years down the track another idea for a story in the same setting came to me - a murder mystery in a small country town. I started entertaining the idea of writing a series of stories in a post-nuclear southwest, although I decided to divorce the setting as far as possible from Fallout by changing the timeline. The Great War of this revised setting took place in the early 21st century, and the stories would be set only about 20 years later. So I started work on the new story - it involved panthers (which were almost extinct), featured an intellectually impaired scrap trader named Tegwyn, had a mention of clockwork powered phonographs, and even referenced the Warlords of the Leeuwin-Naturaliste peninsula. It was narrated by the town doctor who would solve the mystery and apprehend the culprit.
Needless to say, this story again never got further than a few paragraphs. But the idea of a more original post-nuclear southwest setting stayed with me.
It was about this time that the company I worked for started getting a lot of jobs from down south. Pictures and information about the southwest started flowing over my desk and started reacting with the vague details of the setting in my head. Before long I realised that I had everything I needed to create a GURPS game. I bought some maps, did a bit more research, and before long the Wild Southwest was born.
The current version of the setting owes comparatively little to Fallout - although I've kept the ring pulls as a tribute. The tribes of Quest Beyond Time are nowhere to be seen either, and there's no knights on donkeyback questing for gasoline. Chief Deoduce Mulkay of the Xavians definitely never existed. But the Wild Southwest owes a debt to all these works and the people who created them. It's also been influenced by everything from Shakespeare to Firefly with a good dose of steampunk thrown in, and will continue to grow and be influenced by anything that sparks off an idea in my head.
So that's where the setting comes from. Get out there and enjoy it (just don't forget to load your gun and keep an eye out for the sanguaroos).