Hello, I just moved back to the US from Thailand, and a lot of my friends have told me about their food likes and dislikes.
Bread and cheese are not really used in Thai food and could upset her stomach at first.
A lot of thai folks find our food to be too bland, but too salty. They don't use table salt, just peppers, chili, and fish (soy type) sauce. Pizza is not real popular.
A good way to find out what she likes and dislikes is to ask her to cook with you. If you have an asian market nearby, you could take her to by a wok, some spices and together you can teach each other about different foods. Most grocery stores have some basic thai spices in the ethnic food section.
Eating for thais is a very social event, and families try to have at least one meal a day together to talk. Also, things are served in big dishes on the table, and everyone has a little of everything.
She may also enjoy the opportunity to use a kitchen. Most thais don't have one at home, and get a lot of carry out to take back. Your family and guest could have a lot of fun with this.
To introduce her to American food, start with things like roasted chicken and fish, potatoes and pasta dishes. Ice cream is a popular snack, as are potato chips. Thai people also eat a lot of microwave cup-o-noodles type soups, so keep some on hand. If in doubt, just ask her. She may not speak up on her own, but thais will answer that questions honestly because food is so important to them.
Good luck to you!!