True: At least this time, it was late-August in clear weather.
In winter? The snow would have (did!) stop even Lewis & Clark, the Donner Party, Fremont and Kit Carson from walking across those mountains!
That's great country over there between Tetonia, ID and Jackson. Heck, you draw a line from Livingston, MT to Henry's Lake and take it Southeast from there to a line from Cody, Wy to Afton, Wy and you have some of the most beautiful country on God's green earth.