An electronics install is actually pretty trivial. In the last year I have done a few small projects on one of my boats including:

1. Replanked 40% of the bottom (it is a wooden boat)
2. Built a complete new interior (I gutted the interior to reframe the hull)
3. Dig a complete engine install starting with new floors and beds and including a completely new fuel system from the tanks to the engine. The install included full sound proofing of the engine compartment, building a new deck hatch over the engine, installing an automatic fire extinguisher system with an automatic engine shut-down for when/if the fire extinguisher goes off, new batteries and battery box. The install included new engine controls and the cabinet work to mount them.
4. I completely rewired the boat starting at the new battery box I built. That rewiring included new installations of all electronics.
5. I did 100% of the calculations to decide on the correct size and pitch for the prop and had the old prop repitched to the new setting. The new prop performed almost exactly to my calculations.
There are a couple of other things I forget too.

Of course, I do have a fair background in hydraulics and fairly complex electronics from building an operating a scientific lab.