Our cruise will dock at 8 a.m. and leave at 5. Is it possible to get to the park and back in that time period? Any recommended tour companies? THANKS!
With a car, Plitvice is c 3 hours in each direction, so allowing time for getting on and off the boat, you would hardly get any time in Plitvice.
If you are travelling between June and September, there will likely be long queues to get into the park and you won't be able to beat the queues and get there for opening time.
Spend the day in Split or nearby Trogir.
I agree with Jennifer unless you are traveling very, very off-season. I made the mistake of going to Plitvice on a day-trip from Zagreb in August 2015. I waited in line for about an hour just to buy my ticket. When I got into the park, the walkways were packed. It was not a good way to see Plitvice. I can say that definitively because I was lucky enough to visit the park twice before it became so popular.
Split is a great town to tour. Going to PL for a day would be a huge waste of time. The trip from Split to PL is not interesting, and that would be your day. In Split, there is the Palace itself, and there is a terrific Archeology Museum within walking distance of the port. Stay in town. You'll enjoy Split.