Does anyone have any experience doing this as a day trip on a bus or through a travel agency? Travel 49 is mentioned many times in the RS guidebook, but their website doesn't seem to exist anymore. I'd like the option of going on my own on one of the buses out of Split, but it seems like the journey is quite long, which would leave limited time at the park. Then there's the more expensive tour group option, which I'm willing to consider if there anyone can suggest a reputable agency. Thanks!
Very impractical to go to PL and back to Split in one day. PL is about 6-7 hours to do well. Not a full day, but the better part of the day. It is about 5 hours from Split. So if you got up at 3, drove to PL, got there at 9, do the park, and then drive back, you could do that, but life is too short for such nutty idea. Go there in the evening, stay in a soba, do PL early tne next morning and drive back to Split. Or better yet, don't go back to Split - go to Ljubljana - much more interesting.
I found a tour at a moderate price and the ride is half the time you mentioned. We get to spend about 5 hours at the park. I'll be in Ljubljana prior to going to Croatia :-).