Villages GPS sounds good on the surface, but I think it would not be financially viable. Too many different platforms to develop for: iOS, Android, Others ???? But, I'm no expert here.
Plus, after you are here for a while, you get the hang of the cart path designs and the GPS is not necessary, nor is the $5 map.
GPS will not stop folks from taking the wrong turn or just ignoring the directions. The GPS in my car would tell you that is a true statement..
Hint: if you have an Android Smartphone, you can use Google Navigate to drive the cart paths. GPS will show your current location, as you drive and the cart paths are visible in the google earth mode. Not sure what the iPhone has these days, for navigation.
Happy carting . . . and keep all 4 wheels on the ground!