Please throw couple ideas for 500-800 bike tour south of DC. The tour can start anywhere with a good (cheap) multi-day parking (or Amtrak train station with baggage service), and can end anywhere on Amtrak train station with baggage service.
I have done Cleveland->Pittsburgh -> C&O last year, and looking for some change of scenery. Planned travel time: end of August. I live just north of DC, so preferably either a starting point or an end point should be close to DC area.
So far, I am considering
The outer banks
On the other hand, I think I would really enjoy something more inland, such as revisiting the GreenBrier river trail, but I do not see an easy way to incorporate it as a part of any bike route.
Nice scenery is preferable, some camping availability would be good.