I can honestly say that when towing I have never delayed anyone at a pump. I try to stop at large multi pump stations, I know I am going to take up two pump stations so I will pass on a busy station.
Also, large truck stop type stations generally have lot of turn around room, so they are my top choice.
Out west the smaller remote towns do not have such opportunities but they also do not have the volume of traffic.
On vacation I fill up with at half a tank, I do not worry about cost, I have an extra 5 gallons in the truck bed and I goes for convenience and ease on maneuvering at the pumps.