Mapquest assumes you drive the posted speed limit. v=d/t so at 164 miles from 5108 Birchleaf to Hillsville, VA you would average 54.06 mph. We have to believe JY averaged 66.5 mph to make in in 2 hours and 25 minutes OR 12.44 mph OVER the speed limit.
I have a hard time getting past the following items required to believe JY did the murder himself.
1) I don't believe he would have risked stopping for gas, much less stealing gas in King, NC. He would have filled up once he arrived in Hillsville.
2) I don't believe he would risk speeding (by an average of 12.4 mph) after committing murder.
Exactly!!