In my own truck I set my cruise control at 60 mph and be done with it. I stay in the right lane and really don't care about what people think. This is why I am in the right lane. And I know my st tires are rated at 65mph and yes the odd time I have had to pass someone I go above that sped rating but not for long.
At 60mph in my truck I am at 2700 rpm. And some big hills the truck will drop down to second gear and max out at 4500 rpm. Yet again no big deal as after having the truck on the dyno it makes its max tourqe at 4500 rpm. And that is towing with a/c running and holding 60 mph.
My truck is a chevy colorado with the inline 5. With the 4 speed auto so towing must be done in third gear. So even if you looked at a v8 colorado you still may have to tow in third gear. I also added a transmission color and my transmission and coolent temps have always stayed in check.
But please slow down we are camping so I really see no rush to get any where as I have my home behind me.