Take the second exit west from the round-about into Belgrade.
Come into town, and go through the first 4-way stop to the second 4-way stop at Jackrabbit Lane.
Turn left on Jackrabbit/Highway 85, and take this south over I-90 and approximately 8 miles to the stoplight in Four Corners.
Continue heading south, taking Highway 191 (Highway 85 splits off to the west) into the Gallatin Canyon.
Continue south on 191 along the Gallatin River for about 33 miles to the traffic light at Big Sky. (Lone Mountain Trail)
From here, it’s another 12 miles and you’ll see the sign for the 320 on your left, at mile marker 36.