Don't under estimate the heat from the exhaust..... our Ducato Camper van heater exhaust exits pointing down about 10-12 inches from the ground.....generates enough heat to wilt grass after a nights stop ..... I'd be inclined to duct it into the chassis section ;-)Cant see from the photo. You obviously know all about combustion areas like with house flues. does it not bother you how hot the exhaust pipe gets? I may be being paranoid. just interested.