re: catalytic heaters... I use them as space heaters and once lighted they are flameless...mine sit at an angle to the floor, but after my original comment, I used a plastic bottle stand from my single burner stove to set it vertical...the actual heating "head" might be a little large to sit on the floorboard without interfering with the dash... the pictures of the vertical unit on Coleman's web site appear to be a little smaller, and would be my choice... they are available with piezo electric starters but would naturally back it up...don't know what your daytime summer temps are but I think I would remove the gas bottles

I think I would give the Dietz lantern and kerosine a test if living in that type of climate...the W T Kirkman Co. does not recommend the use of paraffin based lamp oil (of which I am guilty) so will probably get a new wick and a supply of kerosine for next years hurricane season...light in a parked car on a highway is probably a good thing...