We spent the night anchored in good sand off Oven Rock, and went exploring in the morning. We had heard about a trail going up hill to a sink/cavern that dropped to a cool liquid grotto, and we were determined we were going to find it.
Allen and I walked the beach area until we found a likely looking trail, towards the northern end of the curved beach north of Oven Rock, and trekked off, armed with machetes for the undergrowth. (One thing I learned from hiking is, you need to give back, aka trail maintenance.) The trail split off in several directions, and we followed various trails until we eventually found the cavern. It was well worth it.
The cavern does a manageable elevation drop to get down to the water grotto at the bottom. There is enough light to see the way out, but you definitely want a light to explore with. The cavern is large enough that it is a welcome cool from the surrounding summer heat, and an interesting place to look around. I had heard that the water in the grotto was fresh, but, it is not. I think that means that the cavern must drop to sea level. The water that drips from the ceiling is fresh, forming beautiful stalagtites, and stalagmites. Someone had placed a 5 gallon bucket there to collect water. It was nice and cold where it dripped from the rocks.
The water in the grotto was also cold, which was a refreshing change since we'd gotten pretty warm hiking around. We swam for a little while, and I decided that the next trip I'd bring a mask and a dive light! 
When we left the cavern, we followed the trail over to the east side of the island, and scoured the beach there for treasures among the flotsam. We found a couple of sea beans, and some various larger objects that I had to pry from Allen's hands as I insisted they weren't going back to the boat. I did persuade him to leave them in a picnic looking area where there were already a various assortment of interesting flotsam.
