Welcome aboard.
Yes it's a bit blokey, but there are a few ladies participating, and hopefully getting the car advice they need.
If you buy a Mustang 30 years or older, it comes into Oz duty free automatically, so there's no financial incentive to hold it for a year.
65/66 cars are good property, and the 66 has the more modern dash. The best sellers seem to be C code and A code V8's. Coupes are cheapest, then convertibles and fastbacks. 67/68 fastbacks and Mach 1's seem to be in short supply, and in demand. Be careful if you are offered a pricey GT, as there are a lot of dollied up cars around. Consult this forum before committing.
Given you and hubby are not car savvy, it's very good advice to use one of the Aussies in the USA to source a car for you. Then book them to arrange shipping when you are ready to return.
Ripoff merchants abound in old cars, and you don't want someone's rust bucket. Keep in mind body repairs have become hugely expensive in recent years due to the cost of labour and overheads.