(1) Congratulations!  
(2) You're joking about filtered air for the heat, right?  That fan is your
leaking fuel line sensor relay.  It relays smell of gas to the sensor on 
your face.  Actually the air ABOVE the engine is pretty clean -- it gets
about eleventy changes a minute because the engine draws so much.  The air
BELOW the engine is cozy warm but otherwise nasty.  This is why you need
a good seal to keep ABOVE and BELOW separate.
(3) If the blower fan spins when it is supposed to and doesn't make squawking
noises, that's probably as good as it gets.  Pretty easy to get a second
fan and put one on each tube, to double your heat, if you feel you need 
more.

Good luck w/bus and bambino
B.
Wm Kennedy
kennedy@admin.njit.edu