The route looks OK at best... There are to many large city's to deal with, I would avoid Atlanta like the plague !
I have done plenty of these IBA rides in the past from SS to almost all the extreme rides and here is my suggestion. Start at I-85 and 76 exit # 19 take 85 N to 77N to 81 N exit Williamsport MD junction rt. 11& 81 distance 522 miles. There are plenty of gas stations here plus a Mickey D's . Document properly and double back to start point . Total miles 1045 time 15 hours 8 min, 70 mph average. You will do well..