Set the kml_balloonstyle_text attribute, which tells Google Earth to just use the description for the feature balloon, rather than the default, which contains the links for "Directions to Here" and "Directions from Here".
Please see the attached workspace.
Removing "Directions" from KML Balloons
Article Number: 000002335 - Last Modified: Aug 17, 2012
By default a KML balloon will contain links "Directions to Here" and "Directions from Here" (driving directions). This example shows how to remove these links from the balloon.