I did not catch this the first time:
we loaded the expedition up like normal(basically folded 3rd row down and filled with gear) and then hooked up the trailer.
With a 32' trailer, what could you possible need to haul in the TV:h
If you can not find enough storage in that size TT for a family of four....you have packing issues. :S
Try loading the trailer :B preferable over the axels. This should lighten the payload on your TV. You may even be able to reduce some of the tongue weight.
Much of that "wiggle" tends to come from to much payload (as where a sway is caused by too much on rear of trailer). Getting some weight off those wiggly rear tires and suspension, may be enough to get you more in control for occassional trips. Many, long trips....refer to my 80% rule.
You can always tow much more than you can haul...load that big box, not that spot designated for groceries.