Is it possible to bookmark a link that, when chosen, will automatically open up new document (a word processing document in this case) in Google Documents even if I don't have GD open at the time? Having such a link would be a bit of timesaver for me.
You can indeed. Looking at the HTTP traffic, when you click the button to create a new document, it goes to https://docs.google.com/document/create first. I've checked and you can hit this page directly and it will do just what you want.
As noted by Ava, you can also use:
You can also create new documents, spreadsheets, and presentations straight from the following URLs:
As far as I can see there is no easy way of doing so. When you create a new document, the window that opens already has the document ID in its URL, so this means the ID must be created and stored by Google Docs before you can actually start editing.
So I would say, no, it is not possible, because you would have to have an ID in the document editor.
I threw the files necessary to do this properly into a github repo if anyone wants to use it! https://github.com/kyletns/quick-docs