I bet there is a way to do exactly that, but I am not aware of it, and it didn't make itself extremely obvious but I can think of a couple less than ideal solutions:
You can protect the document (Tools | Protect Document) from tracked changes, then people can change and save the document, but their changes will be "tracked" in a different formatting and your original document will be remembered. When it comes back to you, unprotect the document the same way you protected it, then go to Tools | Track Changes | Accept or Reject Changes... and then just reject all changes. It will revert to the document you sent off in the first place.
Second, and probably closer to what you want, you could save the document as a web page. That way it will be viewable but no cursor will appear and it cannot be edited, although it will open in Explorer instead of Word. I don't have much experience in saving as a web page, so I don't know if all of your formatting and everything will look exactly as it does in Word, but in my limited experience it seems to work pretty well. Good luck!
