Some have to create the polygon with the corners of the map and att to the GenericPolyChecker.
The problem is if i am not mistaken is that the coordinates on the USGS topographical map is in another datum then geocaches uses NAD27 and WGS84.
So they have to be converted. If you don't do that the border will be off by 87 meters by longitude
If you like to do it the checker is easy to create. Contacte me directly if you want help with how to do the convertion and the format of the the checker