It doesn't bother me if some one is going 55-60 mph on a 75 mph rural interstate. Having logged over 1.2 million miles in a 11 year period pulling non rv trailers for a living out here on the roads I've learned there are many reasons others don't drive like I do nor do some folks pulling rv trailers need to keep up with the flow anywhere.
With the Dodge/Cummins it runs great at 65-67 mph on a rural interstate pulling my 11400 lb rv trailer.
Running 2 lane roads depends on road conditions ie; hilly/twisty or flat open roads.
We all have different destinations and time constraints to get there quick as possible vs others who have no constraints and take it slow and easy in the right lane.
Hell I'm on I-44 just about every day. I-44 runs NE to SW from ST Louis to Wichita TX so gobs of rv transport uses it. Not towing I run the 75 mph speed limit. I pass some rv transporters but about as many pass me.
Just be safe out here and learn to drive respectfully however fast you drive.