Mitch,
It seems you've got it figured out to me.
The traction battery you have with 7 volts is well and truely gone, so it is out of the equation for the moment. It will drop to 0 volts if you probably put a low wattage bulb across it....
Your plan is fine and although you'll not be able to put any significant load on the machine it should allow intial diagnosis of the problem by a tech, well atleast show any fault codes.
This is ONLY to be used to report flooding, spam, advertising and problematic (harassing, abusive or crude) posts.