Visited in early 1990s. There was a lot less graffiti then. At the time, it had two or three tight belly crawls in some areas lasting for about 5 feet (for a 6’1, 180lb person) and we dug a few inches down in the wet sand to get through. It didn’t appear that anyone else had ventured into the tight areas.
There was also a small cave that went about 50′ in the opposite direction of the main traveled route (basically behind the ladder)
Entrance to the lava tube - photo via google (not mine)... https://static.panoramio.com.storage.googleapis.com/photos/large/62168243.jpg