The motor powering our RV isn't finicky ... it doesn't care what speed we cruise at and remains pretty laid back and easy going all the way up to 4000 RPM.
With our rig's 4:56 rear diff ratio and oversize tires, 2000 RPM works out to be about 57-58 MPH. This is a speed range that gets us the best fuel mileage considering the RV's frontal wind resistance, allows us to stay safe by moving along behind big rigs, and makes it possible to enjoy soothing music while traveling without white knuckles or high blood pressure.
The quiet side of life.