I'm on a similar cruise right now and we did the Princess pre-cruise hotel in LA. The pickup from the airport was just the hotel shuttle but we were met by Princess reps and escorted. The hotel was nice (airport Marriott). The next morning was a bit of a hassle as we had to put our suitcases out to be picked up by 8, and then we had to lurk around in the lobby for around an hour waiting for the transfer. But all in all I was happy with it.
In FLL, the airport is so near the cruise port I wouldn't bother doing the Princess package. Also, you probably don't need a post-cruise hotel unless you want to enjoy Fort Lauderdale on your own after the cruise.