Australia is roughly the size of the continental US with a tenth the population and we still have lots of small roads in the populated coastal green bits, so I'm not sure what your point is.

It can be harder to find a safe route somewhere in the country, I'll give you that.

Australia like Western Europe can be traveled near sea level. For example, Bern, Geneva and Zurich are all less than 500m.

The US is not like that. There are only a few routes in the west because the west is more than a thousand miles of mountains and deserts nearly all above 1500m and much of it above 2000m.

It is hundreds of miles between north south routes in Arizona because of the Grand Canyon. And the eastern route goes from vast remoteness to vast remoteness, Navajo nation to the Great Basin (an internal drainage the size of France).

I am not a general fan of American exceptionalism. But for geography, it holds. The average height of the Colorado Plateau is about 2000m…almost as high as the highest point in Australia. And the plateau is larger than Germany.

I am glad it works on your machine.

Hey, I've lived in the US, and it's big enough that you need to specify where you're talking about. If for some reason your bicycle tour is going to take you around all of Arizona, that's a problem. If you're Californian and you don't live in the Sierras, what you've said doesn't hold as much, nor if you live in the Great Plains or New England.

This is vaguely similar to Australia, which has gigantic deserts with terrible roads through them as most of the landmass, but geographically bikeable population centres where everyone actually lives.