I frequently tow a 25' travel trailer (2013 Nash 23 D) Tongue wt approx 530# Gross Wt Approx 6500#. Anyone have experience pulling a trailer akin to this one? I currently have an '08 Tundra 5.7 Double Cab w/hiboy truck cap. Am experiencing range from mid 7's to 10mpg. No problem pulling trailer but it hasn't met a gas station it doesn't like. Definitely looking for improvement. I'd appreciate your input.