I would love to have a big BonVoyage party before we cruise... But, for several reasons. Doesn't look like it is meant to be.
I am just full of ideas though! I would set it up like a 'preview' of the cruise. Get a Disney/
DCL image online to print up your invitations. Or, perhaps they could look similar to a 'Ticket' for the cruise.
Set up your entry to resemble a cruise. Make a large WELCOME sign, with your party's name and cruise date, etc... Perhaps even use ribbon to set up a kind of entry queue....
any PartyStore/PaperFactory/Etc. will have tropical decorations.... If you dont already happen to have real palm type trees (Ohhhh you do live in FL!!!!), you can even get large paper ones to make your deck/patio/or outdoor area look tropical and festive. How about stringing up some lights and/or flags etc to look very nautical and festive.
Set up a large table that would resemble a nice cruise spread, you know, nice tablecloths, etc... with a huge centerpiece or decoration made from things like tropical fruits, etc....
Would you happen to have a friend, a High-Schooler who babysits, or anyone else who would be able to perhaps dress the part and help to 'serve' at your party.... That would be way cool!!!
I would definately have some great music... Depending on your preference, you could go "laVida Mickey", "Low key Caribbean", "Mexican fiesta - (if you were going on the Western...), etc.. We have a 4-nite Bahamas cruise planned - and I am definatley ready to party - so I would crank up "Who Let The Dogs Out!!!" Conga like stuff for sure!
You didn't mention what 'syle' you would prefer. What kind of budget, etc... But I hope this helps get some ideas going for you!