When you go on the road, you start off with the wind at your front. (The odds-makers don't concede 3 points to the home team out of the goodness of their hearts).
The 800 lb gorilla sits in the stands at away games. Crowd-noise creates problems for young teams, certain QB's and offensive systems which rely heavily on complex audibles and snap-counts. (How many false start penalties do we average on the road)?
That said - I do think some coaches are very good at game-planning differently for road games than they do at home. In the NHL, part of the common language often refers to a team "playing a typical road game." What they mean by this is playing dull, conservative hockey designed to "take the crowd out of the game" in the hope they can keep the score close so that they have a chance to steal it in the final period.
And I also believe that some coaches and team leaders do a better job than others of selling their team on "how cool it feels to play the role of 'villain' and get boo'd in enemy country." Those teams feed on this, and it helps them.
I'm not so sure I buy into the "night before" and pre-game road prep arguments, but it woulld make an interesting color piece for Kent, Wolf or Darren to write about - specifically "'a game-day in the life' on the road" vs. "'a game-day in the life' at home" for the Cardinals.