plywood box 6ftw x7ftH 3ftD
Cutting the top third off of a plastic 55gallon drum to put on top, maybe a 4 or 6" PVC pipe headed to the cieling
Buy a cheap round card table thats between 3 and 4ft across. Mount that on the front, then put a bunch of fake bolt heads on it. I mold and cast my own, but they are available commercially. (If you want I will do a video on casting them.)
Rich made a killer boiler door out of wood a while back
I made a (not killer) quickie door out of foam. So foam is another great option.
cutting vents and letting guests see a flicker light inside (vents in the door) will help the illusion (dont forget sound).
Then paint and detail.