The ten-day Southern Caribbean itineraries will operate round trip from Ft. Lauderdale rather than from San Juan. I have not seen the details as to ports of call on these itineraries, but the brochures should be available shortly.
The ten-day "Round Trip Panama Canal" itinerary operated by MV Sun Princess will be similar to the current itineraries operated by MV Crown Princess. There usually are a few variations on this itinerary depending upon availability of various ports of call.
MV Crown Princess may have the best itineraries of all for her last season in the Princess fleet. She will offer three basic itineraries -- a fifteen-day "Classic Panama Canal" route operating between Fort Lauderdale and San Diego, a ten-day "Hawaii" itinerary operating between Ensenada and Honolulu, and a ten-day "Hawaii/Tahiti" itinerary operating between Honolulu and Papeete. The "Round Trip Panama Canal" itinerary really caught my attention, as it calls at several of the best ports that I have seen, both in the Caribbean (Ocho Rios, Grand Cayman, and Aruba) and along the Pacific coast of Costa Rica and Mexico (Puntarenas, Acapulco, and Cabo San Lucas).
Do enjoy, whichever you choose!