If your hauling with a 3/4 ton (F-250, 2500) you shouldn't need a weight distribution hitch. A half ton you might but I've never towed with a half ton. I've hauled jeeps thousands of miles. I have an 18' bumper pull now with 5200# axles. Pulls strait with no issues. One with 3500 lb axles would be fine but gets close to the weight rating of what the trailer will haul, if you want to go by the books anyway.... As for length of a trailer my jku measures 16' so a 16' trailer would be absolute minimum.