Apart from the obvious Nasa/observatory locations have you tried looking at US astronomical society websites and seeing if any events they may run may line up when you visit an area in the USA. One example if your into the outdoors is Yosemite valley {Yosemite national park-California} at Glacier point, a congregation area for amateurs astronomers
http://photo.whiteoaks.com/2006-07-2...ite/index.html