Ok here goes a longer personal list:
1, give the entire unit a basic inspection, look for loose wires, missing or damaged parts, loose or damaged hoses, including inside the control box and any clues about its history (service and unit markings, any date markings). Using a deep well socket on the fan nut (remove plug from fan shroud if needed) make sure the engine turn over by hand, there is no since in going through all the other stuff if it does not. Some people will say you should pull and inspect the injection pump first, I personally risk it vs the amount of work pulling the pump requires.
2, check fuel tank, clean, and repair as needed, I know a lot of people have ended up with bad fuel tanks, personally I have been lucky, I have bought about 10 or 11 pieces of diesel powered military equipment (generators, air compressors, water pump, heater, etc.) and only 2 have required flushing of the fuel tanks, and those two both had minimal corrosion / gunk issues. In fact my MEP-002 came with a brand new tank and brand new filters already installed, just a dead AVR output transistor.
3, check and change filters as needed, don't forget the little filters in the bottom of each of the 3 electric fuel pumps. Chances are good that you may not need a new air filter, these filters are massively oversized for typical conditions, although if it spend time in the sandbox all bets are off.
4, make sure the cold / warm operations lever on the air cleaner assembly is in the Warm position, cold is for arctic operation only.
5, connect batteries, and confirm operation of the pop out dc breaker.
6, put some diesel in the fuel tank (I like to mix in some ATF or Marvel Mystery oil to help break down any gunk in the fuel system), fill with oil confirm operation of the fuel gauge, and low fuel sensor
7, turn main rotary switch to the run position, prime the fuel system, confirm operation of both inline primary and secondary electric fuel pumps, and look for fuel leaks.
8, attempt to preheat and start, there is time to check / replace the glow plugs later if needed, remember switch must be held in start position until oil pressure comes up, it is not exactly like starting a car.
9, only run for a few seconds, shut down, check again for leaks, if it failed to start check glow plugs, priming, and bleeding injectors, etc. I have found that many units were left with enough fuel in the lines that the injectors don't need to be bled. Glow plugs are generally only needed for starting on cooler weather, exact temperature depends on the unit, how much compression it has, how strong of starter, etc.
10, restart adjust speed for 60 hz operation, and proper AC voltage at the onboard outlet best confirmed with a good multi meter or a "kill-a-watt P4400" then check that the DC charging system is charging the batteries. If no AC output check to see if the small AC circuit breaker is tripped, if not cycle it a couple of times and test with a meter before looking for obscure things (learned this one recently the hard way)
At this point trouble shoot remaining issues, and hopefully you are up and running. In general don't trust the panel meters for accuracy.
Ike