While I think you are correct in general the pp brought up a couple good points as well. The bigger issue may be the mechanical components of the tow system ie actual hitch on the tow vehicle, hitch attachment strength, frame strength back there stuff like that. However if as you stated the tow package changes nothing but coolers and alt that should be ok too. It is not like you are towing 5000lbs you are really only over 400ish lbs of the exisitng tow capacity but still well under the tow package rating. And if you keep the tv well under its max gvwr I think it would be ok. I would certainly keep my eye on tranny and oil temps. the Alternator should not prove to be a real issue since towed vehicle will only be using some tail lights, blinkers etc.
Is this going to be regular thing or every once in while, short distance, long distance, flat or hilly, mountainous?
