Good analysis, but you're dead wrong here. First off, they don't have the bodies to do a 'crew change'. We barely have enough bodies in the armed forces to take on Iraq, much less fight another regional conflict. Second, the men and women onboard are already trained and ready - a crew change is definitely not happening.
Schedule for the ship while it was back in port for 4 weeks.
Out of area leave takers get first leave period and the local leave takers take the second leave period (not everytime, just what I think happened for this special circumstance).
Onload replacement equipment, fix troublesome systems, add newer crewmembers that normally would be airmailed to the ship but with the buildup taking up all cargo aircraft this frees up cargo space.
And most importantly, add more nukes and offload pregnant chicks.