I live near Danville, VA, and from what I've read it's some of the best trails around. I will echo what the others have said, though. I've never ridden Roanoke, but judging from the others' comments, it sounds a lot like Danville. In which case, a "trail" bike would be just fine. I've ridden Danville and parts of North Carolina on a 120-ish bike and it's been fine. In Danville there's steady climbs, and occasionally you'll get a flowy downhill, but for me the downhills don't last long enough.
With that said, I'm actually thinking of maybe getting an Enduro bike with 170/160 to ride. I haven't made up my mind. But I feel like I'm done with climbing any way. I just want something I can take to Bryce Resort in Virginia or Beech Mountain in North Carolina. I'm smack dab in the middle of both, 3.5 hours from each.