How do I get through the second part of the Sparkle Caves? (The part where the room is filled with hookshot blocks, but none of them seem to connect to where you need to go to?)

Also, where in the world is the entrance to the desert? I've looked all over for it!

EDIT: I hate to be the guy who keeps asking things, but I've been wandering around the flooded world for two days now, trying to find the entrance to Level 7 and am having no luck. I've got the flippers and Din's Fire; is there something else that I need to get me there? If so, what? If not, where in the world is the entrance?