I don't know the area that well, since it's been a long time since I was out there. But here are some spots that I remember:
It's not far from Cade's Cove, and you can hike a good distance up the river, which is quite scenic, and there are lots of waterfalls around.
There are several hikes there, though solitude might be a bit of a problem.
Gorgeous views -- the best place in the park bar none to get the classic Smoky Mountains look. We went up there at dawn + three times at dusk, and got stormed out every time. Don't hang out there during a thunderstorm.
Beautiful cascades. Not sure about hiking opportunities.
Worth a visit. Around 1 mile each way, IIRC. (There's a picture of the falls in my Large Format gallery)
Lots of hiking opportunities, and lots of cascades. There's a shot from there in my LF gallery also.
For more inspiration, look here:
Danny does a lot of photography out there. He's the one that introduced me to most of those locations during a workshop :)
I hope that helps!
Sorry I don't have much advice to offer about where to car-camp, but hopefully someone else who knows that area better than I do does :)