Does a Lincoln Navigator with a 5.4 make a decent tow vehicle? As I understand it the rear suspension has air bags. Does that mean that an Ford Expedition would be the better choice?
The Navigator should tow very well within it's limits. Payload and rear axle rating are the likely limiting factors. For example, a TT that weighs 5000 pounds dry will likely be 6k loaded with around 800 pounds of tongue weight. If your family weight 500 pounds combined and the vehicle has 1200 pounds of payload, it will be over GVWR. So as you shop, pay attention to all the ratings, not just tow rating.