As for the western United States, I recommend the national parks, but not the cities. Los Angeles, a thriving city of thirteen million people, most of whom who can't afford to live there, is a manic wasteland, oddly decentralised and homogeneously indistinct. Las Vegas, shortly put, is the most horrifyingly ungenuine and base place I've ever visited in my life. And lastly, I never really appreciated the ability to buy fresh fruits and vegetables until I spent a month in that wasteland of fast and processed food - to this very day, I startle awake some nights in a fever, flashing back to that one time I saw a watermelon that cost $18.
But those national parks... they are worth it.