First of all I would check in at the closest custom's office to where you enter the waters. You want to make sure that you tell them it is a private boat so they don't charge you the charter prices. It might even be smart to have a notarized letter from the captain stating that you have permission to use his/her boat for pleasure and that is borrowed not chartered. It would probably be a whole lot easier if the captain just left it in the BVI for you to get to.
To second this don’t clear at Spanish Town if coming from the USVI. They might not like it. Also make sure the boat is presented for inspection should they choose. That means don’t anchor in CGB and cab to Sopers to clear. They really don’t like that!
G