This is why the gods created diesel engines

wouldn't help there. He had an outboard and only 12 gallons of fuel. But
motoring a LOT is MOTORing a lot.

I know people who won't sail if boat speed drops below 5 knots. Me, I have
been known to sail in winds so lite I was passed by a lobster pot from behind.

would one do as well
to simply drop the main in very light airs and go with the staysail and jib?
Or use the mainsail as well

in lite winds, you choice is pretty much down wind, and twin head sails seems
to be the preferred, though large genoa to one side with main to the other is
also used. The staysail is pretty small and isn't much use most of the time.

If you are willing to take whatever speed you can get and don't want to go much
downwind, a very large lite headsail (cut more flat than usual) and a lite
mainsail can keep you moving, though you VMG upwind usually ain't much, if
anything at all.