Towing in 4th

I made it back on the round trip. Just a hair over 1000 miles. With the trailer weighing 1900 and estimated 1500 worth of added weight/gear/two people to help, I'm guessing I was closer to 4000 in total added weight. Truck overall pulled fine. I was getting between 12-15 mpg which isn't awful. On the trip back, it was easier to just keep it in 4th most of the time and not stare at the RPM's. I did kick it into OD when coasting down long hills though. Just knowing the truck really well, i knew when to shift back into 4th before the torque converter would change. And lastly, it's amazing how horrible those 6x12 trailers tow when empty. They don't sway or anything but they just bounce all over the place. Once i had it all loaded, it pulled completely fine.