get a multimeter and set it to resistance then connect each end to each cable and give it a good waggle, if the numbers jump about then the wire/connector(s) have an issue. Might save you physically eyeballing each and every cable.
I would go with the alternator one though, that can cause lots of problems. Also earths, always check your earths! Get some copper grease and slather it all over the connections when putting earths back on. If the connections are corroded then clean them up with electrical contact cleaner/ file/ anything abrasive to scrape the corrosion off. They're not the best to begin with, now they're minimum 22 years old, imagine how much moisture has touched them, how many hot/ cold cycles they've been through. If the cable can move with the engine, e.g. the earth by the charger, that cable has flexed with every movement of the engine so could be breaking in the middle under the sheathing.