I hijacked this from another website and it has some good info regarding winter camping.
Winter hiking with an overnight or two?
1ST: KNOW THE LOCAL UPCOMING WEATHER BETTER THAN THE LOCAL WEATHER FORECASTER DOES and plan on it being ten degrees colder than anyone is predicting. Winter camping is very gear intensive - you might be able to get away with a 3 season tent if you are 100% sure there will not be falling snow BUT you'd still want at least a -20 degree bag. You'll need a closed cell pad AND a inflatable foam pad, the first to insulate you from the frozen ground and the other to provide additional insulation and comfort. (One needs to protect themselves more from the frozen ground than from the air in winter) Spend more time packing down the snow for your tent than a reasonable person probably would and you'll sleep much warmer. Pack but DO NOT clear away the snow as it is a great insulator. Must haves: silk underwear, very good boots (Well insulated with a plastic shell much preferred) PLENTY of layers, two VERY good pairs of mittens/gloves with full synthetic liners, two hats, wool socks, ear warmers, a balaclava, a waterproof/near waterproof soft shell, etc etc. NO COTTON ANYTHING!!
Cooking: make SURE you get a four-season mix if you're hiking in with a propane/butane stove and relying on it for drinking water and cooking. Easy prep, high calorie, high carb food should be the only items on the menu.
Liquids: Gatorade freezes at a lower temp than water does (high sodium content) so use it exclusively if need be; it's readily available in powder form and easy to carry. You need to HAVE TO stay hydrated in winter... even more so in the summer. Humidity levels can fall to near zero when it's below freezing and you will lose a good part of your fluids by just exhaling when you breathe. To boot, you need plenty of fliuds just to maintain and generate body heat. Make sure you wrap your water bottle and bring plenty of fuel if you do not know if you will have access to liquid water; melting snow for fluids will quickly drain your fuel stock. Want to live? Keep the BOOZE at home as it deregulates your perceived body temp, causing you to feel warmer than you really are. A few drinks?? A casually bad idea can potentially turn deadly very quickly.
Good firewood can also be hard to come by in the winter so do not rely on it as a heating or a cooking source. It's enough to warm your hands and face and maintain your spirits but not much beyond that.
Remember: early March might sound like the beginning of spring down here but up there, it's still very much winter. Leave your dog at home on this one! Most dogs are now just as domesticated as we are and cannot reasonably handle a winter overnight without proper shelter and good bedding.
With this event? Unless you're feeling particularly robust and already well stocked with winter gear OR looking at unseasonably warm temps for the outing, you might just want to make a day of it, hang out for the campfire and trek back to the car before the night really settles in.