Unless you've added a governor spring kit or a box that raises your max RPM capability, you won't hurt the engine by winding it up. The 5.9 was built to drag around medium duty trucks weighing up around 28,000 pounds. These trucks are usually geared so that top speed is 62 to 65 mph. When you drive a truck like this on the highway, you just floor it and hold the pedal down. They run for hundreds of thousands of miles this way, at max governed RPM.
Specific example: the company I work for has a Ford 26k GVW truck with the 5.9 and an automatic. The automatic is set up so RPM is never under 2500 under load, and the truck will do 62 mph foot to the floor. The only time this engine runs under 2500 RPM is idling at a light or coasting. The truck has around 120k on it with oil changes at 7500 miles if somebody remembers, and it runs fine.
The point of all this is to show you that the 5.9 is really overbuilt for what most of us are doing, and that towing all day at 3000 rpm is a picnic compared to what these engines were designed to survive.