Hi everyone,
winter has already started, but maybe this could be helpful to you for next year mountain biking season:
www.bikingspots.ch
This is a site I started this year, where people can explore/upload/download moutain bike tracks as GPX or KML files (for GPS units and Smartphones).
Site is in french, but following a track on a map should not be such a big problem

...
Have fun !
Seb