Fall and thinking about HEAT,

one item I've been considering for vehicle preheating and while camping
where electric is available is a Kitchen Toe kick Electric Space heater.
it should fit nicely in the base of my cabinet. or possibly a thin
raised section between the front seats.
http://www.houseneeds.com/shop/HeatingProducts/heatingunits/electrical/mysonelectricaltoekickheaters.htm

For hot water whiel Camped, I stumbled upon this hot water system?
http://www.hotcampshowers.com/new51788.html

I've seen a van with a tank (where your large battery is atm) and had
3/8" copper coolant lines run thru it.

also a small heat exchanger for baseboard hot water systems like this
would be pretty efficient
http://www.houseneeds.com/shop/HeatingProducts/HydronicHeating/heatexchangers/mischeatexchangers/heatexchangermainpage.htm

the only problem I could see is your car coolant runs to above bioling,
it would need a T-stat or flow control to minimize boiling of the house
water. or a way for steam to be released.  I seem to recall a webpage
that illustrated making a hot water tank under the rear bed/seat.

any warm thoughts on this kind of hot water systems?