the steering box is adjustable to compensate for this normal ware and tare,
if its no longer adjustable then it needs to be rebuilt $$$ - if it is
actually the steering box, which it most likley is.
the liquid gas you talk of is "liquified petrolium gas" it is very popular
in australia too, the good thing is, it runs completly independant of the
normal fuel system, so if/when your $1000 fuel distributor dies, you can
continue driving the car without issue on LPG till you get it fixed.
rust is a problem, as soon as you start fixing it, you will find more, and
more, never assume its isolated to just the place where its visable.