We did Emerald Princess Panama Canal cruise over Christmas/New Year's and arrived at the Los Angeles Cruise Terminal on Jan 6.
We took the Princess transfer to LAX.
Worst decision of my travel life. Totally disorganized, people standing around waiting (including those dumped there off wheel chairs), no communication on transfer schedule, etc... So, getting off the ship at 0830 with arrival at LAX shortly after noon.
Fortunately, I had booked a hotel stay thatnight with flight next day.
Pre-arrange a taxi or other shuttle service. No more expensive and far more reliable.