Move DC to Texas
---- more specifically. Mentone,Texas
Or to Texas County, Missouri, which was the center of population for the US in the 2010 census. It may have shifted a bit further south and west by now. Springfield would be the closest reasonably large city.
Or go by geographical center of the 48 contiguous states, which is in Smith Co., in northern Kansas. That's pretty rural so maybe a nearby metropolis like Salina, KS, or Hastings, NE, could serve as the capital. Housing would be a lot cheaper and Congress might not stay in session year-round.