It sounds like a sweet deal doesn't it. Someone pays you to visit these exotic locales, try their food and write up a book about your experiences. As much as this sounds like a dream come true, it isn't as easy as it might seem.
Many travel books, magazines and web sites are looking for people who have already been there. If they are writing a book or want a story about Disneyworld restaurants, they want someone that has been there, do some research and write something up. These places don't want to pay a contract writer to visit these places.