If you are getting cash get it here before you go.
+1
You should only need it for small value transactions, use credit card for the rest. We were in the USA on holiday last year and split the cash between my wife and myself. She managed to lose her wallet on the flight over. When you lose cash there is no comeback.
Try to figure what you might need ahead of going over and bring that, e.g. $ X times Y days. If you run short there are ATMs but you'll get charged for using them, and the USD EUR rate won't be competitive.