Back when Pirates cave was open you would jump from Pirates and swim in to the cave, the cave had two exits to the top, one came out at Push Carts side of the road and one came out across the street commonly called Josephs' Cave. Well we all now know Pirates is closed, check across the street to see if they still have an entrance, I believe it was an iron welded ladder to the top, it may have rotted out now, hence no way out! Have had boat guys take us through other caves you could actually drive a boat through, I don't know where exactally but any of the Negril boat guys will know, suggest a boat cruise to see from water then note each entrance and ask boat people.