3 miles or so paved climb right at the start.
16 miles of single track on the way out
38.5 miles of gravel roads
10 miles of single track on the way back
2-3 miles of pavement to the finish
BF is approximately 15 miles of trail at the beginning and end with a 30 mile hilly gravel grinder in the middle. I did it 2 years ago when the weather was perfect. Might try again this year.