Mike,
You can create a link in the PDF to the Word document stored on a LAN drive, web/sharepoint site, etc. Keep in mind that the link is absolute pathing - meaning it needs to be the same for all recipients.
An alternate method might be to embed the Word document inside the PDF with instructions in the PDF on how to get at it. The down-side to this method is that some security tools have alerts and blocks place one PDFs that contain embedded file attachments.
Unfortunately, there is no perfect situation.
Hope this helps.
Thanks - Doug