winter polycultures are fun and easy in NC. No bugs or diseases to cause problems from Nov-Mar. A single layer of floating row cover or a single layer hoop house works very well to keep just about any cold hardy crops alive and growing through most of the winter. I lived in Durham (piedmont area of NC), so your specific location may be a bit different.
Nice combinations of salad greens that we liked included common ingredients such as lettuces and spinach, as well as arugula, sorrel, chard and asian greens (mizuna, tatsoi, etc...). If you start now, you can still get a batch of carrots/beets/turnips/daikons to hold over through the winter, too.
Don't forget the "weeds" - chickweed and miner's lettuce will be getting started growing soon and will help round out the
polyculture with a bit of encouragement.