In addition to a reasonably high quality mechanical torque wrench, I also carry a 2 foot long breaker bar, which uses the same socket as the torque wrench. Leverage is often important when trying to loosen lug nuts. Have never used one of those electronic torque adapters, but they look interesting. Don't forget to be certain the jack for your tow vehicle will work on the trailer frame, or else carry a separate one. Since I now have a dual axle trailer, I bought one of the Anderson lifters that will get both wheels off the ground.
2009 Tacoma Crew Cab, TRD 4WD
2007 Tundra Double Cab TRD 4WD
2014 Escape 19
2007 Norwegian Elkhound "Baxter"