Possible Clues:

• Take on fuel, in a routine suggested by the first words of 20-, 34-, 41-, and 55-Across
• Get a fuel fill
• Fill with fuel
• Go from E to F, in a way
• Top off the tank
• Compliment, in modern lingo
• Get the fuel gauge to F
• Fill one’s tank
• Trip prep step
• Prepare for the long haul?