Trailer towing hookup questions

Rodney, The truck we used was a GM 1500. It had the 'heavy duty tow package' just never had the brake control installed. Ran that at 30-40 and the trailer played nice. Also, he has extended cab and a cap with heavy tool boxes.
With the Duster back wheels between the drop loops, the back of the car was near the back of the trailer. It sunk just a little under tongue weight till he added air to the bags. He installed the air bags when he was using it as a service truck. ( With the boxes load with tools it sat on the frame) FYI, we did come back over Peter's mountain - I think I saw Stefan sweating a bit on that one and the AC was working fine. LOL