If you install a simple in line jacket water heater as is available at your
FLAPS, you would accomplish the preheat issue on your engine, plus you could
run the rear heater from a separate loop, with spare battery power.....have
your cake and eat it too. Only laziness and looong ass, butt busting winters
like this one have kept me from doing this. So what's my excuse for not
doing this during the long ass summer? Summer, that's what!
Sorry Scott, you probably said something similar, but I'm saving your post
for  later...........ha!
Thanks,
Miguel