I think you're on the right track. Again, forum rules don't allow us to link to another travel site. Try to look for back to back 7 night different itineraries. Example, on my most recent cruise, that ship (Freedom of the Seas) does the Western Caribbean one week, then the Eastern Caribbean the next week.
I'm not sure if there are any ships in RCI's fleet that do a 14 night Caribbean cruise.
2007 - Majesty of the Seas (Bahamas)
2009 - Enchantment of the Seas (Western Caribbean)
2010 - Freedom of the Seas (Western Caribbean)
2013 - Golden Princess (Alaska, roundtrip from Seattle)