In my opinion the rated load is what the truck could handle all day, every day, running the speed limit or maybe even a little more on an interstate in the desert on a hot summer day or whatever bad scenario you might encounter. If you slow down some, especially on bumps and turns, are going short distances in mild weather, the truck can handle quite a bit more. Just be aware of the load and how it affects your truck and you can get away with quite a bit. A case in point is pulling a space shuttle with a Tundra. I am sure that was way over the truck's rated towing capacity but was endorsed and even promoted by Toyota.
