I enjoy cold weather camping. It's part of the program.
I avoid heaters with tents. My thought being if I need a heater because my bag is inadequate and the heater fails, I'm screwed. My best bag is good down to -20F. Never been cold, sometimes overheat. I've learned the challenge is how to be comfortable before retiring. Around the campfire I have made use of snow boots. Love my flannel lined jeans. Could wear a layer under those if need be. I bought a big warm parka that was cheap so I don't worry about hot embers. Keep the skin covered. A good warm head-cover. If sitting around a campfire (recommended) use an additional blanket for your seat and back.
"...Tucson to Tucumcari, Tehachapi to Tonapah"