TPC distinguishes between KML files that were created by TPC and files produced by some other programs.
If you import a KML file that wasn't exported by TPC, every Placemark in the KML file will be imported as a traverse. In Google Earth a placemark can be a line, polyline, point, etc.
If you import a KML file that was exported by TPC, almost all the data you exported can be imported back into TPC.
Icon data stored in the KML file is not imported.
All surfaces in the KML file are imported into TPC. The source and border traverse (if applicable) are automatically imported in when TPC reads the KML file. If the surface uses all TOPO points as its source then it looks for TOPO data in the "Points" folder.
TIN and Breaklines aren't imported. Enough data to recreate the surface is imported and TPC expects TIN and Breaklines to be reenabled in the surface settings dialog.
TPC will always import all traverses from this folder. Line color and line width will be brought back into TPC.
Lot labels tagged on a traverse when it was exported will be retagged when that traverse is imported back into TPC.
Sideshot points found under the SideShots folder will also be imported and added to the traverse associated to those sideshot points.
All points in this folder will simply be added to the survey's points.
If you exported a TPC drawing to KML and then import it back into TPC, TPC creates a new drawing and adds these drawing entities to the layers they came from. When a drawing being imported contains QvText entities, TPC recreates those QvText entities exactly the way they were using their original font, font size, and color.
These settings can be changed from the Import dialog by clicking the gear icon with Google KML selected as the type. When you click the gear icon you will load the KML Settings dialog and from there you can make changes to the import settings for KML.
Google Earth KML
KML / KMZ Import Export Settings