As I mentioned, as far as I am aware, iTunes does not sync documents, such as .doc files, because the basic iPad does not have a native app that supports them. So you need to transfer documents from your PC/Mac to the iPad by some other means. The easiest way is to email it to yourself from your PC but collect the email on your iPad.
Another way is to use a cloud server, such as Apple's MobileMe, which gives you the opportunity to upload documents from your PC to their cloud server iDisk and then, from your iPad, download those documents from iDisk.
There are also a number of third-party apps available that will let you transfer documents directly from your (wireless) PC to the iPad - such as GoodReader and PrintCentral.
Tim
Scotland