若米国有人手头有euro, 不妨换些.
其它,就没啥必要了.
护照最好放旅馆的保险箱里.
再make a copy of your passport, put it online.
Just in case that your passport is stolen or lost.
you can use your copy of passport to get into US consulate to get a new passport.
Otherwise, it will be very difficult for you enter into US consulate.