Big Walker? No IIRC it was interstate. I remember going through the tunnel. Really the most scared I got on a mountain was on Jellico Mountain. I had driven about all night coming down from Chicago and hit a blizard in northern Indiana somewhere.
We got to the Kentucky side of Jellico headed south and my partner woke up and said OK I'll take it now. We both didn't have that much driving experience but I knew that mountain real well. I said get over there and strap yourself in I know this mountain curve for curve and hill by hill. We got up about three quarters and he looked down the mountain. He got kinda green around the gills LOL.
My favorite white-knuckle drive (East Coast) is Sharon Springs Road coming down out of Burke’s Garden from the south; which is just a bit to the southwest of Big Walker Tunnel. A narrow, unpaved nightmare of switchbacks and drop-offs that will have the most seasoned driver sweating. Man...my wife and I prayed all the way down. :-)