Two weeks is going to be difficult to get in visits to two major cities on opposite coasts. Travel time alone once in the US between SF and NY is going to eat at least one full day.

Your best bet is to pick a general area and see what you can there. So if SF is a higher priority, expand it out to see the northwest. If NY is a priority, plenty of things to see down the east coast as well.

Think of it this way. Your wanting to visit a country larger then the continental Europe land mass, and one that also has a similar amount of diversity in things to do, cultures to experience, and areas to explore. I spent 3 weeks in Europe and still only traveled inside of 4 countries.