This idea of everyone going the same speed is not very realistic.
Most highways in America with speed limits of 70 or more have light traffic. Give people space. The faster you drive, the more room everyone needs especially if you are towing.
Ever drive the Autobahn in Germany? They have extreme differences in speed. The number one (right hand lane) are trucks going 45-50 mph. In the number two lane are mostly cars and faster trucks in the 60-70 range. In the number three or more lanes are people going 90, 100, or even 130 mph or more. People do not change lanes without changing speed. That is how you stay safe.
If you are towing, be mindful of your stopping distance.