I was tring to see just how accurate my map was calibrated, so I decided to make a track file which drew out all the grids on the Maine Gazateer. It took a lot of hand editing but it works great. The photo below shows how it would show up in USAPhotomaps. It could also be converted to other formats, or even uploaded to your GPS.

The track file in CSV format is here. (Works with USAPhotomaps)
The track file in Mapsource format is here.