Goofing around on forums reading about custom maps, and I reverse engineered a link and was surprised to see this folder allows listing of contents:
http://www.garmindeveloper.com/apps/GarminCustomMaps/
You can download all of the KMZ files that Garmin has created directly from that link. I checked out a couple and they are pretty nice.
It is much easier to go directly to that link / folder than drill through all the forum postings in the forum below to find the same maps...
https://forums.garmin.com/forumdisplay.php?f=206
Perhaps this isn't the biggest hack in the world, and perhaps it has been discussed before, but perhaps someone will find it handy...
Dave
Very Nice!
Very nice.
:)