Speed varied a lot on that 350 mile trip.
This is the best way to break in a new car.
Driving at a constant speed (or with cruise control) harms the engine of a new car.

When I was alone on the road and it was safe I drove as slowly as 45 MPH.
When necessary for safety I drove as fast as 70 MPH.
But I always tried to accelerate gently and allowed to car to slow down some going up hills.

Need fewer troops to support.
Drive a hybrid.
Best tank 71.65 MPG.

Before this car I spent two years learning hypermiling on my 2004 HCH1.