Like everyone has said sweat is going to be the biggest factor especially for staying warm at night. The winter camping I've done I've always planed a complete separate set of sleeping clothes and forced myself to change into them prior to getting in the sleeping bag or more importantly forced myself to change back into my day clothes before leaving the shelter. Yes everything goes in the bottom of the sleeping bag. I use to have a lightweight cover for my sleeping bag it wasn't a true bivy but it definitely gave the bag an extra ten degrees of warmth and a little extra protection from overnight moisture. Kind of like a layering system for your bag's temperature.
Unlike Minnesota & the Northern States, there "might" be snow but most likely you'll encounter soggy ground. Maryland is a disgusting kitchen sponge during the winter months - so you might want to take a good ground tarp for your tent and take that into consideration footwear-wise walking farther into the forest for camping but hey no poison ivy. In general Maryland salts the cr@p out of the roads yet even if the roads look completely clear there are hidden pockets of black ice (normally at the bottom of a hill). Have you thought of looking at Warmshowers? Have fun sounds interesting.