Generally speaking, it’s a bad idea to use fuels in things not meant for them. I don’t know of a lamp would produce enough heat to push CO /CO2 out the chimney- but it’s very likely the lantern is not going to be adequate for all night heat.

It’s also a bad idea to leave lanterns running unattended- though depending on the stove this may be mitigated, it’s not particularly safe.

IMO? If it’s a matter of staying warm, you’ll be better off with plenty of warm blankets or sleeping bags - remember to layer them on top and bottom.

Why not put wood in the wood stove though?

It never hurts to pack a battery-powered carbon monoxide detector when you’re experimenting with something like this.

90% of the heat will go up the chimney. There's got to be a better way. My buddy installed a propane heater in his VW Vanagon. He's a pretty handy guy though

I did a little websearching and found some tent heaters that could probably do fine in a truck camper as well. They're mostly propane-powered but there's a kerosene one on the list with a run time of 8 to 12 hours that's beefy enough to do a whole cabin. Some of the ones listed include oxygen sensors to automatically shut off if they detect poor ventilation, probably a good idea if you're leaving it run overnight.

I suspect that the best approach if you're trying to "improvise" and are worried about poor ventilation would be to not bother keeping the whole space heated overnight and just invest in a really good sleeping bag or some really good blankets. You won't care if the rest of the camper is cold while you're unconscious, only keeping yourself warm matters and with enough insulation your own body heat will suffice for that. I keep a rolled up set of wool blankets in my car just in case I end up skidding off the road in a snowstorm and need to spend a while waiting for help to come, for example. Wool blankets can be quite surprisingly good at keeping you toasty in a cold environment and can be used when you're just sitting around during a frosty day, too.

Hell, a lantern isn't going to heat a tent worth a damn, so expecting it to keep the surface of a metal stove warm enough to heat a bigger area is failboat.

I mean, it's a few degrees, maybe, but once it's inside the stove, that goes away

I wouldn't; the odds of it tipping or otherwise having issues while you're sleeping aren't high, but the risks they present are.

do truck campers have wood stoves?

But yes it should in most cases vent fine as long as doesn't tip and the flue is open enough. Wood stoves sometimes have air intakes near the bottom that aren't designed for flaming liquid.

If you're heating a small area, I recommend a 2kw or 5kw diesel heater. Runs off 12v and diesel or kerosene. Thermostat controlled. Also, a second, isolated battery and like others have said, a carbon monoxide detector.