I would change to disc brakes, which would lower it, if you buy the lowering spindles, but I'd keep the original suspension. I think 60 and 61 were the only ones with torsion bar suspension which gives the truck a nice ride. You might want to install power steering if it's to hard to steer for your son.
Joe

54 Triumph TR2(rhd)needs total resto.
60 Apache 10 stepside shortbed
99 Excelsior Henderson