Yes, it does have the KMZ file which you can use in Google Earth, but that isn't quite the same thing as integrating a resort trail map into the app, so that your 'run' data would show that your second run of the day was on "Andy's Encore" at Copper Mountain, rather than just 'Run 2'. I have taken the GPX output and uploaded it to my cycling site: RidewithGPS.com, and that works quite well too. On the map display on RidewithGPS.com site, the lifts at Copper are displayed, but the trail names are not. Running the KMZ file in preview on Google Earth feels a bit like looking at a NASA flyover animation of some strange planet. Probably works better when you are in some city where their photographers had some street scenes.
The Ski Tracks web site lists their accuracy for most of their data to +/- 5% which I find as reasonable for an app of this nature.