This is true creative thinking!  Wouldn't it be more efficient to use
either gasoline or propane auxiliary heat, though?  If you use direct
electrical heat, you are indirectly heating by burning more gasoline, but
you have considerable efficiency losses in running your engine to turn the
generator.  A 12Kbtu suburban heater in the back and a smaller (Propex or
Carver) heater in the front should do the trick with less retrofitting
problems than installing a big generator.

Still, the big generator has some appeal.  Think of all the accessories you
could add!

Bill 
St. Louis, MO
www.geocities.com/wdummitt