Think it's gonna be cold during the rut? :crazy: :D
For cold weather camping, a good insulating pad is a must. You might even buy two of them just for good measure. Or, if you have a big enough tent (one you can stand up in), get a double high airbed. That's what I use when I go camping. If you have a cot, you should still use the a pad for insulation.
Get a good sleeping bag. Make sure it does NOT have any cotton in it. A good synthetic or down bag rated to 20 dgerees or lower would be best. Also invest in a sleeping bag liner. I like the Sea to Summit Reactor liner, which is made of thermolite. It certainly made a difference to me.
I don't use heaters in my tent.