Put a nice rock by the fire and at bed time wrap it in a towel and put it at the feet of your wife's bag. toasty feet go a long way towards happiness.

Electric blanket.
Extension cord.
DC/AC Inverter that only draws when the truck is running.
Remote start on the truck.
Toasty.

while camping earlier in January, up in Georgia, the temp in the tent was 14F.
My bag was rated to zero. My tent was NOT a three season, but with a U Haul packing quilt and a Thermarest pad under the air mattress, a heat reflective pad on top, and then the bag, I was warm as toast.

Well, until I had to get out.

What size is the tent? We use the regular buddy heater in a 10x10. Works just fine & if you wake up cold in the night just reach over & fire it up. We have used it down to -30 but the tent is polypro & just the fly is nylon so it doesn't condensate like a backpacking tent would. We have used it in the small tent as well put it in the vestibule & just run it for awhile before bed & again in the morning.
I think the big buddy might be to much for most tents, unless they are really big.

In a nylon backpacking tent you get a lot of condensation as mentioned.

One thing I have done in a small canvas tent is use a coffe can with toilet paper stuffed in it and soaked with rubbing alcohol. Put the lid on it and take it with you till you need it.

You REALLY have to be on the ball with it tho when you light it so you don't burn your tent down.....just had to be said.

We use a Mr. Heater and leave a lantern on to deal with the moisture issue. Since I'm a sissy, I also use some of those little air activated toe warmers with the adhesive tape on them. Slap one on each kidney and sleep well all night.

I, too, was in S. georgia, tent camping while hunting the first week of January last month. Temps were in the high teens.

I always take my 0 deg bag along in winter as you never know what temps will be like from day to day.

I do, however, take a small Coleman Cataletic (sp?)heater that runs on 1-lb propane cylinders. I turn it on at night before I lay down. It knocks off the chill while I get undressed. I do it again in the morning to heat up my clothes for the morning hunt.

One comment I will make is that I am convinced that sleeping without insulating clothes, in a good bag, is warmer than sleeping with insulated clothes on. For me, it is underwear and that's it. I stay warmer and the bag can do it's job that way.

By the way, the coleman heater says it does not put off Carbon Dioxide but I don't sleep with it as I just don't trust it. It says you will be fine and is even called a tent heater but again, I don't want to "wake up" dead......

I have camped with wood stoves & various propane heaters & an old Coleman catalytic heater. The catalytic heater is over 30 years old & runs on Coleman fuel. I have slept some chilly nights in a tent with this heater. Several years ago a friend & I camped on an island in the Gulf of Mexico with high winds & temp down to below freezing. A small propane catalytic heater kept us comfortable to undress at night & dress in the morning. We only ran about an hour at a time & a single bottle of propane lasted 4 nights. I have used the toilet tissue heater many times in a boat fishing in the winter. Many ways to stay warm when camping other than endure chilly balls.

Funny story about those old Coleman cat heaters using coleman fuel.I wen t hunting with a guy many years ago who had a slide in pick up camper and we pulled off the freeway on the way to hunt, to grab some shuteye.He lit the heater and we went to bed.Got up the enxt morning and he let it in the camper lit,and we went down the road.A little while later we smelled smoke and pulled over.Ran around back and opened the door.His down bag had come off the upper bunk and landed on the heater and was smoking.You don't ever want to sleep in a camper that smells like burnt duck feathers. UGH!!!