many modern appliances use what are called universal input power supplies. Look at the product label, if it says 100-240V or VAC it is universal input and will work fine on any world mains voltage. I am not saying all appliances are like that.
Going back to the US is a serious culture shock. Be prepared for everyone around you being angry and on edge, and everything will be crazy expensive. And if somebody asks you, Trump is your God. Good luck.
I just contacted the hotels directly was not a problem. Watch out for the 3rd party cancelation policies. If you are dealing directly with the hotels they will usually work with you if there is a change of plans.