I removed the cab from my USMC M813A1 over the summer has part of the process of tearing it down. Now while I did not have to deal with the steering box because it has a 2 piece steering column, everything else is the same. I removed everything attached to the firewall on the exterior and I removed all wiring from the cab. This included removing the dash and gauges but I did leave all of the fittings on the inside of the firewall, all of those will have to be moved to the new cab eventually however.
To make it easier to lift, I stripped it out further than I had to. I removed the windshield, top, drivers door, seats, and tunnel covers. Looking back, I should of removed the passenger door because it make lifting it off dicey (should of seen it come but hindsight it 20/20) but the hinge was too mangled. You will have to remove the T case/PTO handles because they are bolted to the cab. I unbolted mine as a set directly from the cab crossmember.
Watch your speedometer cable, I forgot mine was on and only realized it was still attached to the cab when the cab was in the air. Also, do not forget your fuel tank breather lines which maybe bolted to the bottom of the cab. If your truck has a fording kit like mine did (USMC truck), you will have to check all of the other breather lines as well. If your truck has a slave cable, remember the ground which is bolted to the frame. I think that is about it. I will try to post some photos this weekend.