That's how I would do it. Launch word and keep it invisible while you load the appropriate template and the information from VFP. If you're looking at extensive 'boilerplating', it may make sense to store paragraphs in fox tables and pick & choose at run time based on the type of letter. That would be easier to manage than a large collection of Word templates.
Check out the book from Hentzenwerke "Office Automation with VFP," There's awesome power in this approach.