Just learn bathroom and you are set!

Actually I know what you mean. I use to work in guest relations for anime conventions and that meant I had to work with a lot of Japanese people. Some from bands, some voice actors, some who are artists you get the picture. And I had to learn a few phrases to work with them. Usually they would have a handler with them that would help with the talking but when there wasn't one I was responsible for them. I had to learn things like, "This way" "Through that door." General numbers so they would know the room keys. And as you said, one word can mean a 100 different things and I had to be careful in how I would say what little I knew.