The D7000 will do just fine in those temps. The battery will drain more quickly than usual but it not too bad until you get into single digit temps. Then the drain can be fairly fast. I keep a second battery in an inside pocket, next to my skin, so that it stays warm. When you battery starts getting low just swap out the cold battery with the warm one and put the cold one in the same pocket. After a while the first battery will warm up and regain most of its charge. In temps of around 20°F I can shoot for 4 or 5 hours and only need to swap batteries once near the end of the day. When you get closer to 10°F you may need to change batteries in about an hour.
I never have any serious issues with condensation in the clod of winter as the humidity is usually low outside and in the house when I return.
Dress in layers and make sure that you find some gloves that allow you to use the camera controls and still keep your hands relatively warm. That said, your hands are likely to get cold so get some chemical hand warmers and put them inside your gloves and a set in your coat pocket so that you get your hands warm quickly.