As you can see on the map if you zoom in a little, the nearest train station is Lus-la-Croix-Haute. The trip from Grenoble takes about an hour and a half, it should appear as a result on the SNCF website, or you can see the timetable [here][1]. To reach Vaunières, maybe you could use a taxi or a car rental, I am not able to find any public transport option.


  [1]: http://telechargement.ter-sncf.com/Images/Rhone_Alpes/Tridion/63aff_V2_2014_tcm-31-19895.pdf