I may be too late to help this discussion but I own a 2011 Ford Explorer. When you put the transmission in Neutral the steering will NOT lock, so you don't have to worry about removing the lock key. I tow four down and the mileage does not add. I used to put it in Accessory but found I can turn the key to the off position and almost everything turns off. (The only thing that appears to continue to run is the light on the gear selector which apparently is not many amps.) If you do have a drain on your battery (because of using battery power for your braking system, or your brake lights come on, or what ever reason), I would install the TOAD CHARGE as mentioned above.
>> Dennis