Please use option 3 - (or option 2 if you're hardcore). There is a great article from some intrepid MVPs here: How to Use IncludeText Fields
But here is the basics in Word 2007:
In the quick parts menu, select field:
In the field dialog box, just enter in the filename (or URL if you're one of the Happy SharePoint People like me)
When the sub document is updated, the main document will be updated too.
Easy!
Years ago when I did word processing as a specialty for a living, you could set macros to repeat things that had to be done over and over while doing a document. It could be repeating 4 words or underling certain words. You used the "F" keys to assign each macro. How do you do that on Office 2007 Word?