Jason: Thanks for the information. The main reason I chose Delta to STT is the miles make it a free flight and (I assume) that wouldn't be the case for the code share link. I know the pros and cons of separate tickets which is one concern with using interCaribbean out of SJU but there are options if there are flight issues. Last trip a certain unnamed member of our party forgot to take her Bonine before getting on the ferry and that wasn't a pleasant experience!

MrEZgoin: I'll check the charter price. $1400 isn't all that much more than paying for 5 tickets SJU to EIS. It didn't take much arm twisting to convince my group to extend. Having enough available pto is the issue for one traveler.