You should be able to go a few hundred miles on a tank of gas, assuming a normal Ford or Chevy chassis with a ca. 55 gallon tank. I wouldn't worry about gas station availability on any of the Eastern Interstates in the least; just start thinking about refilling when you get to maybe half a tank and you'll easily be all right.
Interstate 64 does have some pretty decent grades, but nothing at all impossible to manage. You should be just fine if you practice basic sound hill driving: downshifting as needed on descents, etc. Use tow-haul mode and (especially if you have a Ford V10) don't be afraid to let the engine rev. The V10 is not a low-rpm truck engine.