If I understand you correctly, you have a image of a maze or you'll design one and you want to import this image in a GPS program using a US map.
Then you want to export this image as a gps Track (path) to a handheld gps device and you want to etch out this image into the corn by simply following the Track on your handheld device.
It's a piece of cake that you can do in less than 30 minutes with just basic knowledge.
You just need a Garmin "on the trail" device and Garmin's Basecamp

This is what I've created on a farm NE of Dundee,MI

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starting with this image

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