Much thanks to Bill Hollings for the tip on replacing the fuel level
sender without removing the tank, now that *I've already done it* I see
that this would definitely be the way to go!  Actually it wasn't TOO,
terrible: 3 hours and lots of gasoline everywhere.  If anyone needs to
remove their gas tank from a pancake-engine bus with the engine in, I'll
gladly give you the run-down from my experience.

Cheers, Tim

p.s. the moral of this story = send for advice from the list more than two
days before attempting the job!  ;)