Disclaimer, this was what happened to me a few years ago.
When you commission out of Newport, your orders to PCola will have a Report No Earlier Than and No Later Than date (or at least mine did a few years ago) for travel down. Mine was commission on 29 Jan, Report NET 31 Jan, NLT 02 Feb. That was four days total, the drive realistically takes 2 days.
You may be able to take a few days of leave in route if you call ahead to the Student Control folks and ask. Those would come out of your leave balance.
Some folks may have more recent gouge on whats up.
EDIT: Also, seriously, I know your gung ho, but trim up some personal info you're putting on here. Don't make yourself known before showing up to OCS.