Pay attention to the recommendation on tire pressure. Your owner's manual should have an insert saying something about tire pressure at sustained highway speeds. Some miss that little tidbit of information.
Basically, inflate your truck and trailer tires to the max recommended tire pressure and be sure to visually check them at each fillup. I use an IR thermometer from Radio Shack to check tread temperatures and trailer axle bearing temperatures.
If you find a tire running hotter than the others, then suspect a low inflation or punture. Also, trailer tire running temperatures will tell you if your trailer is loaded evenly.
If you pull up to a truck stop and have to wait, jump out and shoot the tire/bearing temperature. If you can fill up immediately, I start the pump and then walk around checking the temps.
Last year I did 20K miles pulling our tripple axle, 20K pound trailer. I discovered two punctures before they went flat. They were not visually low on tire pressure, but the thermometer does not lie.
Be safe. Have a great trip!