Thanks for the info! Yes, have heard good things about Apulit!

Apparently the Underground River can't be done the same day as going to Apulit because the boat leaves so early from the dock, and the Underground River is so far away from everything else. So I think we will just do the fireflies the day we arrive to PPS, and then take a van to Apulit.

I think we will go with Daytrippers Palawan. The other option I found was called Camarih, but they have relatively fewer reviews on TripAdvisor, even though they are substantially cheaper. If anyone has experience with them (or another company) would appreciate any remarks.