I really hope someone will point you to a few options because I'm looking for the same thing!
Here's the realization I've come to for now about mid-Atlantic BPing of that length: If you don't think about a clear point-to-point like they get our west, but either think about circuitous loops or very serpentine point-to-points, you'll find several options. (And now here's hoping that someone responds by saying I'm crazy and giving some examples!
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I've messed around with a few selfmade routes but I haven't found anything that I think is worth recomending, yet. I've done a few loops around the Pisgah National Forest in western NC and one of the aformentioned point-to-points from Ivestor Gap to Linville Falls that got to over 200 miles when including the ride home. My biggest hope was for a route I plotted, then rode with my wife, from Damascus to north of Fincastle VA. That general heading still has my interest but there were some significant sections that were on the NatGeo Maps but not on the ground...read - bear trail. And some super slow sections that weren't HAB.
Good luck!