As he’s done for a few years in a row (2013, 2012, 2011), Dennis at CyclingTheAlps.com has built some great tools to help track the Tour de France in Google Earth.
Each course features a map overview, elevation profile, and a 3D tour. Check it all out for yourself at https://www.cyclingthealps.com/#tour-de-france-2014-stages. The race starts on July 5, be sure to keep an eye on Cycling the Alps to see what the riders are up against at each stage.