Dallas, Miami, and Seattle travel the most amount of miles each year.
Neither Miami or Dallas belong in the "east" divisions of their conferences and are only in those divisions because of the traditional rivalries that the league used to rely on to generate interest. Seattle is far away from eevryone so not a lot you can do, plus they are in the "west" division already.
Dallas would make much more sense playing Arizona, Denver, and Las Vegas. The Phoenix and Las Vegas areas have huge Cowboy fan bases, plus I would love to play in two more domes. Denver would be the only annual cold-weather game and that would only be if they played there late season.
Nashville, New Orleans, and yes, Houston would also make sense.
I get the old school rivalries. I just don't think they are necessary any more. Philadelphia and Washington are awful stadiums and environments, and New Jersey is no picnic either, so I would not miss those annual road games at all.