I-26 has a 6% 3 mile+ up-grade going north/west just inside NC; also several other shorter up and down grades as you come further into the state, including a 7% for about 3/4 mile.
I-40 EB has a 20 mile stretch at & inside the NC border that runs thru Pigeon River Gorge. Lots of truck traffic and wrecks, plenty of curves but a very gentle grade, since it basically follows the river. It does feel narrow, since the roadbed bench is carved out of the side of the mountain. There's no median; the east-west traffic is separated by a concrete guardrail. Truck traffic is limited to 50 mph and the right lane. Best to just take a place in that line and go with them. One tunnel WB, two EB, IIRC. Not so much a dangerous road as one requiring respect and attention.
Nice rest areas entering NC on both 26 & 40. I've overnighted in both with no hassles.
Jim, "Old age comes at a bad time."