I wish I had the real print, because I don't trust my monitor on the highlights, which look blown out here. I'm guessing the highlights are fine. It looks beautiful.
If it were mine, I would burn down the sand to help put emphasis on the rock. The sand is a large area and I don't think it brings anything to the photo except the spacial relationship. I would make it quite dark. The top shadows look very dark here. I hope that is the case. I might burn those to black if there is much there. I would try a slight crop along the bottom. In the lower right is a slightly out-of-focus rock that conflicts with the rest of the rock. It also looks to be softening in the corner. Try cropping up to take this out and de-emphise the tension here. Make sure that the brightess highlight in the rock is not at the edge of the picture. If it is, burn it down a touch to bring the eye back into the picture.
This is great! There is a cave like this at Garrapata that I have tried to shoot the three times I have been there. Everytime I get set up, the tide rolls in and drenches me. Very good work, I'd live to see the fiber print!