I have always towed with a WDH. I think the safety issues to be concerned with is braking. The WDH essentially pushes the front end of the truck down and keeps the front wheels on the ground.
What I have experienced towing something else very heavy, on a truck that was too light for it, the front wheels actually lifted off the ground coming to an aggressive stop.
I'm sure you've already tried it by now, but I think you can probably get away without a WDH for 20 miles at 45 MPH in a RAM 1500, just be cautious.