One of my favourite bloggers has a post titled How to set up retention and deletion policies for files and folders in SharePoint which I think would be worth your time to read.
To answer one of your questions "
...leaving a shortcut behind": yes, this is possible, it is known as 'In-place Records Management', the final section in this MS post will help you somewhat. He is a screen-shot of how it looks in SP (note - my screenshot is of a Library-based Policy, rather than a Content Type-based Policy. If the menu looks a little different, that is why).
Regarding your question on Drop-Off Libraries, this post has some info on how they work. I've not used these or read all of the post, but I understand the principle. I've used Information Management Policies - I imagine that you want to be able to configure a Policy to transfer a document to different location (a Drop Off Library) once certain conditions have been met e.g. 3 years after Creation Date. It looks like that would be possible, as you see in the picture above.