I have had my WACOM Intuos for years now. I still love it. It is large, and the actual writing surface is 9 X 12″. I always dream of using a Cintiq, but it is waaay out of by budget. Yes, smaller tablets do have scale issues when transferring to the monitor. Fortunately the Intuos has a feature that makes it exact to your monitor and there is no having to “mouse over” to your next position.
I think it is possible to write on a Word document, I think you need to somehow change the format from a document to a img, be it jpg., or gif. I have never tried it though. I would guess that when you have finished your editing, you can them either print out a hard copy, or change the format back to its original format. However….That seems like a lot of extra effort for your result.