Yes, it can be slow. I imagine the 65 mpg in the Ranger was predominantly low speed pulse and glide (ie. 2nd gear - it's a manual), with an average speed somewhere in the 20-25 mph area. I don't think he could have pulled off that mileage in a straight draft.
I've driven with Wayne as well. In all situations, he's
highly aware of the driving environment unfolding in front of him and adjusts his technique accordingly.
Very little fuel is ever converted to brake dust. That's "driving without brakes, or DWB".
In sub/urban driving or stop & crawl, the engine is either accelerating the vehicle, or it's off, period.
He's more comfortable with the occasional drafting situation than I am.
And he's apparently immune to the sound of honking horns.
Granted, in the couple of situations where people beeped, they had nowhere else to go and were only fixated on his "slow car" (relative to traffic in the adjacent lanes). If they had looked ahead, they'd have seen he was coasting towards either a stop ahead or a slowdown in traffic in his lane.
The only time I felt uneasy was in a free flow of highway traffic, where he's comfortable at lower speeds (right lane, of course) than I am. "Driving with load / target driving" somewhere north of where the top gear or torque converter engages.