"Then what can we place them on that's both secretive and continuously moving?"
The enchanted path is a hidden path, "weaving through the kingdoms like a snake, never traveling in the same direction and never leaving a trail behind it".
It is used in A Grimm Warning to hide the kingdoms' kings and queens from the threat of the Grande Armée. Alex does the magic, but it is Conner's idea, inspired by the Grimms' fairy tale The Secret Castle from the time capsule. The path can only be found be people who know about it.