Hi,
The brief calls for you to create a valley that is inspired by one from the country of your origin; so the question here is ... could you consider a country that you were not born in the country of your origin?
(I'm guessing that you weren't born in the US).
I think it would be easy to argue that the US is the country of your origin if your parents were American. Or your grandparents, or great grand parents. I'd say it's a bit hard to argue that the US is your country of origin if you'd only lived there for a year ... so unless you can come up with a strong argument I'd go back to the first environment (I'm sure your original environment will benefit from your extra experience).
Regarding altering the environment to suit the architecture and furnishings ... yes absolutely, but think of it as a negotiation between the different elements.
Cheers