The hand wave could be that there was a pre-planned shakedown cruise with specific waypoints after which, by the time they'd get to Vulcan, it would be four days from then.Hmm. I'll see you that and raise you Mr. Scott at the end of TMP, on the newly refit Enterprise: "We can have ye back on Vulcan in four days, Mr. Spock..."
I know, I know. Speed of plot and all that rot. Nobody seems to like my canon-preserving idea that Spock and T'Pring weren't actually about to get it on when duty called, and it didn't appear either was going through ponn far...![]()