1) Relax! Breath!
2) Alot of people stay at the Raddison night before. I've stayed there too. Very nice pool area. They have suites that will sleep 5.
http://www.radisson.com/capecanaveralfl
3) Personally we like boarding ship as early as possible to start the vacation sooner so I would skip the Space Center, save till Saturday when you get off ship.
4) Pro of Disney Excursions: If you are late getting back the ship will wait for you. Con: Price is a little higher then booking on your own. If you check out site
http://www.shoretrips.com/ its another service for booking on your own. If you are interested in a private sail or fishing boat I can get you info on that. This link is a great info on beaches in St. Thomas
http://www.usviguide.com/st._thomas...at_charters/st._thomas_day_sail_charters.html. Alot of great beaches! Also, where we dock there is a shopping area and a Cold Stone Creamery (it's a must stop for my DD, even though we have one here 1mi away). I highly recommend the Golden Eagle Catamaran in St. Martin. My kids still talk about it and that was 3 years ago. The snorkling was okay, the boat ride was a blast!!
5) Renting a car is a great option. If you stay at the Raddison you can take car back and the
Avis I believe will shuttle you to the port. Since we live in FL we drive and never used Disney Transportation, but I hear it isn't cheap! With 5 probably cheaper for the car rental. Don't know if you like a beer or cocktail, if you do you can pick it up and bring on board with you. Great way to save some $$.
DCL is okay with this.
6) For the time after the cruise. Check out Ron John Resort. Looks awesome!!
http://www.ronjonresort.com/ I would go to Space Center when you get off the ship. There is always Disney or Universal too. We HATE the parks during the summer, but Universal is great if you stay at one of the onsite hotels (Hard Rock, Royal Pacific, Portofino..all Lowes Hotels). The hotel guest get to go in special quicker line for every ride by showing hotel key. Well worth the extra $ you may spend to stay there. If you give me an idea of what you are thinking for after the cruise I may have other ideas. There is a semi dude ranch around, fishing-lake or ocean, beautiful state parks, or shopping...whatever let me know.
7) Are you still relaxed and breathing?