Spend a night up the North Fork and look at the stars. With no electric lights to compete, they’re particularly bright.
The local café and saloon in Polebridge [1] is called the Northern Lights [2], which are commonly visible.
Links:
[1] http://www.moon.com/destinations/montana/glacier-national-park/north-fork-the-flathead-river
[2] http://www.moon.com/destinations/montana/glacier-national-park/north-fork-the-flathead-river/accommodations-and-food