Pulled boats for many years, now have a Rockwood Minilite 2014s. Pulled by Ford F150 Lariat. Gas mileage went from 16 mpg to 8mpg. Just want to see if this is about the average drop in mpg. Don't see ...
Of course there are many factors involved, driving style, gearing, terrain etc. What you're getting may not be too far out of line.
My truck is an '08 Tundra with the tow package so 4.30 gears and 5.7 motor. TT is a Springdale with a dry weight of 5600, yours appears to be a bit lighter.
With some hills around here, I usually average around 10. I don't drive especially fast or slow.