The U.S. is a large, diverse country with countless scenic options, and different people have different views of what is most scenic. It sounds as if you're planning to spend a whole year here, which will give you the opportunity to see a lot of different things. You'll probably want to spend the summer in the northern half of the country and the winter in the southern half. Many of our most scenic areas are in our National Parks, so I would definitely seek those out. The downside of National Parks, however, is that they are quite popular and you won't be lonely there.
I agree with Jay that if you want to see natural beauty, you may want to spend much of your time in the West. The downside of the West, however, is that everything is so very far apart (but you're used to that in Oz).