This is not rocket science. Have you downloaded the TM's? Read the TM. Then once more. First look at the machine. If the screws all over it looked rusted, buy some replacement screws, nuts and washer now, instead of later, when you want to put it back together.
Take the box off the frame. Then pull out the engine/main gen, set them on the floor and separate them. It is possible to pull them out without pulling the rear housing off, but after having done this a number of times, Its so much easier to just pull the box off first, then go from there.
I never mark wires, as I have from time to time done that, only to find someone had hooked 1-2 wires up wrong. When you mark wires, you simply repeat someones stupid mistake.
Go for it! Someone here will always have an answer to any question you might come up with. I should not take more then a few hours to get it out. A big plus, would be a helper, and overhead lift of some sort.