I'm going to jump on the bandwagon and say test your gear in your backyard first.
Don't have a backyard? Go to a friend or family member that does. Set up your rig and eat your dinner right there outside. Get a feel for what it is truly like in the woods from the safety of a backyard. Its one thing to spend all day out in the environment and go bed already chilled from being in the weather all day, and quite another to rush out of a warm house and tuck straight into the hammock.
I was able to test my gear last winter on our coldest night (24°F, yeah I know not really that cold for most people here) and I actually had too much insulation and had to strip a layer of fleece off when my back was suddenly cold due to the sweat.
As Les Stroud says about deep winter, "You sweat, you die." Practice safely and stay dry.