There are plenty of ways to get MPG higher:
Never stop & never idle is first.
60-mph top speed second.
A half-tonneau bed cover is next (halfway from tailgate to cab) is third.
Best tires for the job are the biggest change. Closed-shoulder Highway Rib.
Plan routing for lowest traffic friction & grade changes. Plan all stops in advance (fuel fill on frontage road same direction of travel, away from metro).
Early departures & arrivals. Majority of miles before noon. Constant use of cruise control.
Overall best route TX to PA would incorporate IH69 & 64 the majority of distance.
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