Thanks for all of the great advice!
The small generator is definitely a good idea, for multiple reasons.
The kerosene heater is still not a bad idea for the price, and its specific purpose.
I suppose, if I go with just the heater, I could also buy two of these. One to move the heat around, and a second one to blow carbon monoxide out of a slightly cracked window...
http://www.suremarineservice.com/737DX-BCS.aspx