"Can anyone tell me what the difference is between a steering box/mast from a '54 vs the earlier ADs?"
The 1954 steering mast has holes in it for the RPO/Accessory turn-signal wire-harness.
And, there is a different "cover/cone" around the steering column, under the steering wheel.
"Can a '52 box/mast be used in a '54?"
I do not know, but, I would bet "yes"; but (again), wait to hear from others.
