you know the harness really isn't that bad as far as accidentally plugging something where is doesn't fit.
the engine harness that goes over the manifold is very simple even with gauges, its maybe 5 connections and the harness really only reaches the areas it needs to.
it would be impossible to connect the water temp to the oil sender they are on opposite sides of the engine and the wires are so short
the top harness is really all that needs to come off to get the engine out.
behind the top of the engine (if you have an automatic) will be 2 connectors, one is the top harness the other is the neutral safety switch for the transmission
if you follow the top harness forward you will have the oil sender connector first(it sits on the back of the block behind the manifold)
next will be the idle up solenoid, or could be adapted to the electric choke if you have one, or could even be disconnected.
next comes the coil red/green wire, then the water temp sensor to the left of the alternator by the heater core hoses.
on the other side would be the alternator harness you have 2 connectors there and one bolted to the battery side of the starter solenoid, there are 3 wires that run to the back of the alternator but you can leave them on the alternator and just take it off as one piece. there is also a black wire with orange strip that connects to the the fender electrical isolator if your car is equipped with one.
just take the connector out of the voltage regulator and your pretty much home free.
take pictures and note the colors of the wires and they style of connectors used.
if your striping out the main engine electrical harness on the chassis that is also pretty easy to remember all the hook ups, its harder to get the plastic clips to come out and not break then anything else.
if you feel overwhelmed break up the job, take it step by step no rush. removing the shock tower re-enforcement plates opens up a whole world.
sometimes the air cleaner base vacuum lines are more confusing.