Below is a rough map showing the outlines of most of the existing Eriador zones, as well as several potential additions. You will notice that some are quite a bit larger than existing zones, and may need to be divided even further. This map is only intended as inspiration and suggestion.
I will be adding some concept stuff to this soon.
Below are links to several of Travisimo's well thought-out region concepts. While some of the details disagree with my concept, they are full of excellent ideas.