There is very little to worry about there. Having your car break down or get bogged in a remote location is a much greater danger, but one that lots of tourists ignore.
Um, Australia is home to some of the most poisonous snakes and spiders on the planet. And outside of major cities, they crawl into people's homes and cars on occasion.
Australian here. What you say is true, but avoid long grass (snakes) when out walking and check under the toilet seat (spiders) before sitting and you'll be fine. More importantly, make sure you look up constantly when around gum trees to avoid sudden and violent drop-bear attacks. The exact number of deaths and injuries caused by drop-bears is keep secret by the Australian government to avoid putting off tourists, but could well be more than zero.
A normal clean toilet is no danger, same as everywhere else in the world, but if you're going to the loo in one of those ramshackle open-to-the-elements rustic outhouses, you might want to check the seat.
Real, but usually only if you have an 'outside toilet'; I had one of these in a WWII-era home located in a country area of Australia, and there would often be red-back spiders + eggs under the seat. Still, easily checked for and destroyed.
Considering that I live in rural Minnesota and if my shoes are left outside in summer, I check them for wasps or snakes before putting them on, I'd go for them being real.
Apart from one or two snakes, the cassowary, and the crocodile, dangerous Australian wildlife is pretty shy and sleepy. Make noise when you walk through scrub and the snakes, if any, will avoid you. The only particularly deadly spider lives only around Sydney, you have to go hunting for it, and there's antivenin for it. I've also never heard about snakes getting into people's cars. Sure, it probably happens, but it's rare if it does.
Yes, the toxicity on paper of Australia's animals is sky-high, but that's not the full story. You're far more at risk of heatstroke than animal problems when travelling Australia.
