Hi Jerry,
The Biltmore House is a must do if you've never seen it. While I don't care for the symbolism, I was in awe of the mass, scale and technology of the place. I think we stayed at the nearest KOA when we saw it.
As for the Great Smoky Mountain Railroad train ride, we really missed the "fall colors". That was the October tours. Still, it was fun to do. If you do it, get first class seating. It's a bit of a premium but the Mac Neil car we rode in was very comfortable and we lucked out with a 4-person table to ourselves. Lunch and dessert were great and all non-alcoholic beverages were included as was souvenir travel mugs and a souvenir bag.
Here's a link to my Facebook albumhttp://www.facebook.com/media/set/?set=a.2539093847294.134645.1552091014&type=1 with a few pics I took on the trip.
While I don't recommend the CG we stayed at, if you do stay here, get pull-through site 64. It's long and FHU. This place has mostly seasonal TTs with roofs and porches built around them (done well) but the roads are narrow to navigate my freight train through. I am NOT looking forward to navigating out of this place.
If we return to the area, I think we'll try Country Boys RV Park. Note that it may also be called Country Girls RV Park. Identity crisis I guess.
Here's a map link to it. Note too that there are closer campgrounds to Bryson City where the train station is, but some are a bit rough and the road (19) gets a bit sketchy or RV towing, IMO.
Jim