They split easy except the flywheels, they can be a pig to get off the first time. They are held on with jib keys. Provided the key is intact then a jib key puller will usually shift them but if the key has been butchered then it is a pita.
To get the head and cylinder off takes 10 minutes, 8 nuts and disconnect the injector. The two flywheels probably make up half the total weight but it is possible to pick an individual one up. The block and crank is the next heaviest and needs a crane of some type though two strong men could lift it with a suitable handle fixed to the head studs.
Most people roll the complete engines on rollers, I lift mine with a trolley jack and put it on rollers when I want to move it in the engine shed.
If you are lucky they often come on trolleys, mine did so I just winched it up into the trailer.
The som's however are seriously heavy.
Dick