Accessible PDF via InD. At Adobe TV —
Image/bitmap question - might ask at the InD Forum: http://forums.adobe.com/community/indesign
Once you've the Tagged output PDF you'll need to post-process with Acrobat Pro to validate.
Some of this can be done with Acrobat Full Check or other programmatic tools. This give a "high level" view.
The nitty-gritty of validation will have to be done by you.
Once the PDF is validated use Acrobat to export / save as to MS Word.
If the PDF is a well-formed tagged PDF what lands in Word will be really rather nice.