I'm glad you guys like it. Though after showing it to my players, we're thinking the colors might not be sufficient for marking zone borders, since google spreadsheets don't let you make borders thicker. My alternate ideas are either to make the border cells consist of the number (so, for example, the door at the top of that sample would have "555555" above it), or simply putting the number in the same cell as the label (so the bottom might read: Street - 2).
Thoughts?