Once in North Carolina, set your sights on a place called Blowing Rock, right on the Blue Ridge Parkway, exit onto highway 321 and it's right there. Cutest little town. Great restaurants all over the very small town. Cute inns and B&B's.
If you don't spend the night at Blowing Rock, continue on south down the Blue Ridge Parkway to Little Switzerland, where you should definitely check into the Switzerland Inn for the night! Panoramic views and front door access to BRP. Mile Post 334 on the map. It has its own restaurant with great food, serving breakfast, lunch and dinner. www.switzerlandinn.com. Right before you get to Little Switzerland, there's the North Carolina Museum of Minerals, if you are into that kind of thing. Just south of Little Switzerland on the Parkway is Mount Mitchell State Park, good for hiking.
South of Little Switzerland about one hour is The Folk Art Center, a major exhibit of mountain crafts and art, including some Indian crafts and artifacts. Has a coffee shop/cafe. Mile post 382. www.southernhighlandguild.org. Now you are just on the northern edge of Asheville, N.C.
Here I will mention that the driving time between Roanoke and Asheville is 4 hours on a road where you can go 55 to 60 MPH. On the Parkway, I would say at least 6 hours because of the reduced speed.
Asheville is a wonderful town. A great stop for restaurants and an overnight stop. You may want to see the Biltmore House, mountain home of the Vanderbilts.
If you want a fantastic hike, try Chimney Rock Park, about 25 miles southeast of Asheville. It's where the movie "Last Of The Mohicans" with Daniel Day Lewis was filmed. The hiking trail is the same one the filmmakers used, and you will recognize certain waterfalls, cliffs from the movie. www.chimneyrockpark.com.
Going south on BRP, you will come to Mt. Pisgah and the Pisgah National Forest. One of the most beautiful places in the mountains. At Mt. Pisgah you will have a cafe, camping area and small motel.
South of Mt. Pisgah, you will be between the Cherokee National Forest and the Great Smokey Mountains National Park. This is where the Blue Ridge Parkway ends. The Smokey Mountains have a lot to offer in the way of hiking trails. The best is Clingman's Dome, a short walk that takes you to a mountain top where there is a "sky view" concrete tower platform, reached by a walkway that winds upward around it.
If I sound very familiar with this area, it is because I am. I have a ton of relatives in Virginia in the area of Charlottesville. I also spent my youth hiking in the Blue Ridge Mountains, Smoky Mountains, and around Asheville with my cousins. If you like to go camping or whitewater kayaking, I've done that too in these areas. Lots of fun.
As far as your flight home. Asheville has an airport and Knoxville TN has an airport. But Charlotte has more flights with more airlines.
If you go as far as the Smoky Mountains, you could hit I40 to Nashville Airport, a drive of only three hours. Would be a short flight for you back home from Nashville, should be pretty inexpensive, too.