Train then bus

Grenoble train station, information + bookings on +33 (0)8 36 35 35 35
Daily high-speed trains 
Paris-Grenoble on a high-speed train: 3hrs15 on average.
http://www.voyages-sncf.com/
 
then connecting bus services:
All year round: ‘CARS REGION’ regular bus service from Grenoble to Villard-de-Lans, via Engins and Lans-en-Vercors (T64 route) with possible connecting service to Autrans-Méaudre in Lans-en-Vercors / Tourist Office (T66 route).
Regular bus service from Grenoble to Villard-de-Lans via Saint-Nizier-du-Moucherotte and Lans-en-Vercors (T65 route).
Please note: No bookings possible, you are not guaranteed a seat on board for some Saturdays and school holidays. Information and Timetables: http://www.carsisere.auvergnerhonealpes.fr
TIMETABLES FOR T64 and T65 ROUTES
TIMETABLES FOR T66 and T67 ROUTES

During the winter season: The TRANSALTITUDE coach service:
Direct services, can be booked online (guaranteed seat), coaches from Grenoble train station to Lans-en-Vercors or Autrans-Méaudre, every Saturday and public holidays from 17/12 to 26/03.
Information and bookings: http://www.transaltitude.fr/