Well, it's been a while since we decided what to do but I said I would report back on it so....
After reading this article -
http://www.milesstair.com/kero_heaters.html
and these reviews -
http://www.tractorsupply.com/home-i...rosene-heater-23-000-btu-3070559#BVRRWidgetID
I bought this heater for $129 -
http://www.tractorsupply.com/home-i...or-radiant-kerosene-heater-23-000-btu-3070559
and this fuel for $38 -
http://www.lowes.com/pd_156587-78-C...rosene&pl=1¤tURL=/pl__0__s?Ntt=kerosene
We read the manual, crack open the three upstairs windows 1 inch when it's running, and have a carbon monoxide detector up there just in case. We've already dry burned and cleaned the filter as directed to do periodically for maintenance. It does not smell bad. Except for a few minutes at start up and shut down, when you can smell some kerosene, any odors just reminds me of that warm smell that fills a room when you burn candles. If the wick is adjusted properly as the instructions say (and pictures show) on the side of the heater, it does not smell bad and burns safely. It also has many safety features such as instant shut off if it is bumped. I think a float in the tank signals when the surface of the fuels moves as it would if you were to try an move it while on.
How does it perform? Wow, that thing makes it nice and toasty!

It burns about 1/4 to 1/2 a tank (2 gallon tank) each time we turn it on (for about 2 hours). We only turn it on during the coldest nights. Those nights are comfy after running the heater for just two hours. The slightly opened windows do not affect the heat in the room.
We also turn on the downstairs heater more often even though it is expensive to do. Mostly we keep the fire going in the morning and start it up again around 4pm.
It can still get cold in general, but we're more comfortable now and can crank up the heater if it is really needed so...
Thank you, all, for you help. I may still go out and buy the heated matress pad, though. That would be heaven.
