I've had a similar vehicle and setup, granted with a bit older Dakota. A trailer with trailer brakes is the way to go. Also, I'd recommend installing a transmission temp gauge, and possibly a transmission cooler. Start with the gauge and you'll be able to see if the cooler is necessary.
For me, the tranny died with 50k on the odometer. I was towing at the limit (6500lb or so) of my model year. The 4.7L had plenty of power, but I figure I was cooking my transmission but didn't know because I couldn't monitor the temperature. The idiot light that turns on when the transmission is too hot never turned on. Also, change the tranny oil on a regular basis.
