Vic, knowing some of the common areas of concern on a particular vehicle can be helpful information to someone who is already firmly grounded in diagnostic principles, but trying to teach someone all the backyard short-cuts before they even learn the basics, is just asking for problems.
I have not recommended ANY repairs.
I recommended that IF it is delivering fuel, that the next logical step would be to determine whether the engine is actually capable of running. This is sound diagnostic logic. If it were a gasoline engine we'd be checking for fuel and spark before doing a compression test, but since a diesel ignites using it's own compression, fuel delivery is the only area to check before moving on to determining the engine's integrity.
I am born and raised in the vehicle repair industry, and have had a long (and more importantly, successful) career in vehicle repair. Countless times during my career, I have had to unscrew things that have been screwed up by others. I've seen some real heartache and financial hardship, a lot of which was completely unnecessary, if they had simply stuck to the fundamentals. Back when we had carburetors, I have seen many perfectly good carburetors rebuilt and/or replaced, when the real problem was a flat cam or a burned valve. When OBD-II became part of our life, I saw many perfectly good EGR valves, EGR position sensors, MAP sensors, and so on get replaced, when the real problem was a plugged catalytic converter. And more recently, I have seen perfectly good ignition modules and cam position sensors get replaced, when the cam drive had failed and the cam wasn't even turning.
And if the vehicle owner thinks an engine job is expensive, wait until they pay some hack to replace a bunch of expensive peripherals that never needed to be replaced in the first place, just to find out that now they have to pay for an engine too. In the vehicle repair profession, we have a moral and ethical responsibility to be good stewards of the vehicle owner's trust regarding their financial resources.