I have hunted there a few times when I lived in Bozeman. I don't have a map of the elk migration routes for Montana yet (been trying to gather the data to make a map), but I know when they get a heavy snow in Yellowstone Park (2-3') the bulls start moving towards Ennis. The pass they use over the Madison Range is a little north of Hebgen Lake.
Want a quick and inexpensive call for Moose? Take an empty 32 ounce coffee can, and make a small slit in the bottom, only about a quarter inch. Then, take one of those really big red rubber bands, the ones that go around big folders. Cut the rubber band to make one long piece.
Now, thread one end of the band and tie a knot on the outside of the can so it won't pull through. Cut the band off on the other side so it is even with the top of the can.
Now, wet your finger,...