Much better time frame/distance covered to only go as far as STJ -- your departing guest will have no problem getting to STT airport - check the Crown Bay ferry option to make it even easier.
If you go to the USVI at least!!! one day earlier you can enjoy a peaceful and quiet anchorage somewhere along the N. Shore on a NPS mooring and have a much shorter sail back to Tortola base - clearing out of the USVI is not necessary [U.S. Citizens?] and JVD or West End are short sails from that side of STJ.