OK I might as well go ahead and give you my .02 cents worth here.
Drop the tire pressure to 60 all around.
Put some weight between the wheel wells in the bed of the truck, about 500 lbs of sandbags or whatever works for you.
That's about as good as it will get without spending huge sums of money on the truck.
Drive it for a few weeks and see if you can live with it. If so great and if not you can trade out the truck or trailer and be done with it. If you focus on the ride of the truck too much you will be miserable for as long as you own it. If you can't make peace with it then trade it out take the hit and move on.
Respectfully,
Solman
