Welcome to the USA! Several things to be aware of over here:
1. The rest rooms often have a disabled booth. There is no key needed, just use it if you need to. Very rarely will it have a sink or a rubbish bin inside however. Just use the common ones.
2. You can leave your nappies in the rubbish bin in your hotel room. I always tip several dollars a day in advance and they are really nice about taking mine out as they clean the room. Sometimes, they leave me extra chocolates!
3. We Yanks will toss anything in the rubbish bin at the campsites. Nappies are quite acceptable for this, though recycling your beer bottles & newspapers is advised.
4. Save all those thin plastic bags from the grocer to put your nappies, wipes, etc. into. While people are used to baby nappies going straight into the rubbish, they freak out at seeing adult nappies. Not sure why, but it does happen.
5. We haven't a clue how to to use a round-about. Be prepared for much stupidity near these.

Have a great trip!