I visited friends in Grenoble a couple of years ago and got a decent look at the area - even went rambling in the hills a bit. Personally, I wouldn't worry too much about getting an authentically alpine look - you can see plenty of the high peaks from Grenoble, but the Vercors itself is firmly in the small mountain/big hill range. Very green, very hilly outside of the river plains (Grenoble itself is flat as a pool table), very rural.