Sorry I don't know about quilt shops in Butte, but there should be some since they have a rather great artist community, or at least there was back in the late 90's. My daughter & I did the drive thru Montana, Idaho and into Washington last summer. We loved the drive. We had been visiting friends in Colorado Springs and then went to WA to visit family. I loved it! The last time I had been thru that part of the world was in 1968.
Hope you get to make the drive and have a wonderful time!