There is not a lot to worry about how it was wired or routed. You will more or less end up about the same look.
Also I recommend an alternator and a voltmeter if that is possible regarding your desire for "original". Those items are for simplicity and reliability and are especially adapted to 12V systems.
I have a whole bunch of info/advice/opinion and you will need lots of help. A complete install takes a lot of posts. Kind of difficult to get a whole rewire job done from a forum. Many different answers/opinions and takes days to answer sometimes. Lots of helpful folks here however.

Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn