I just did the 1,000+ mile trip from the SF area to Montana yesterday and was careful to hand calculate the MPG for the trip. My truck is the old 5.4 V8, 6 speed transmission, 4WD and larger off road tires than OEM. It was fully loaded with all sorts of stuff in the bed and cab, though I didn't tow anything. From the SF area to Reno, I kept the speed down to 65 mph and got a touch under 22 mpg. From Reno through Nevada, Idaho and Montana, I took off the 65 mph limit and got 16.5 mpg (I can only say that I made the trip in 15 hours, so assume that the bulk of the trip was at speeds most people would scold me for).
With a pickup that is shaped like a barn door, frontally, speed really causes a hit to MPG when you get above about 60 mph. If your friend has an ecoboost engine and kept speeds below 65 mph, I can easily see getting 20 mpg, though whatever was being towed was likely very light and aerodynamic. I doubt he'd see 20 mpg at higher speeds or with a substantial load.
So I'll conclude with this...I really like the idea of either a hybrid or BEV pickup, but I also am the type who can drive for many hours at a time without a stop and would never buy any truck that had less than a 500 mile range unloaded. I made two stops between the SF area and Bozeman...one in Reno to refuel (I left SF with half a tank), then in Pocatello, ID to refuel again, use the restroom and get some coffee and food (a 10 minute stop). I know most people drive for a few hours and take a rest break, which makes supercharging feasible, and I'm not the typical customer for an EV, but there's a lot of pickup owners who are like me.
