Re: Battery wiring
2001 might be an Isolator instead of a separator, so that the alternator charge goes to the house batteries but the house systems don't drain the starter. I haven't ever seen one of those, so perhaps that is the correct wiring?
Alternatively, negative is negative is negative, so perhaps it doesn't matter, except that with them... hmm, would it disconnect both batteries if you pulled the combined negative? Maybe a safety feature, whereas in mine if one negative is not disconnected there is still power on that side.