After unlocking the first door with the small key, go over to the wooden platforms on the left and pull out the wind waker. Now preform dry storage off of the platform and break the boards to store the cutscene. Note that this trick must be done quickly to save time.
If you have the bombs early, you can explode the rock on your right side after entering the main room, enter the room behind the rock and explode the wooden gate with a bomb. This way you can get the 2nd small key without having to go around the main room and get through the room with the map, which is faster.
It is also possible to get this small key early without early bombs, but it is harder. First, unlock the door in the first room of DRC with the first small key to get rid of the lock. Go back to the first room, obtain a deku stick from the bokoblin and prepare yourself to bring the stick with you to the next room. To do that, throw the stick in a precise angle towards the door frame and open the door. if you did it correctly, the stick will bounce into the next room with you. Then throw the stick behind the rock and attempt to roll over the rock, which is possible with a good roll and a good angle. Then attempt to bring the stick to the next room with you again. This time it is easier as you just need to walk towards the door, pull out the wind waker to drop the stick and quickly open the door and it will work. Then lit the stick with the fire torch and burn the wooden gate to obtain the 2nd small key early. This optimally saves 15s over getting it normally.
Make sure that you've called Tingle and lower your health to 1/4 of a heart. There are two ledges you can choose to hover to, depending on the items you have and the given situation. You can either decide to hover up to the 2nd floor where the bridge is located, or to the 3rd floor where you can find the cage.
No matter where you hover to, start your hover with a bomb, a tingle bomb or a bomb flower, and heal with the Tingle Tuner when you are above the ledge you want to get to. Hovering in the main room of DRC to a higher level skips half of the dungeon.
If you got the deku leaf early, it is faster to hover to the 3rd floor, as the deku leaf allows you to bypass some slower rooms that you'd otherwise have to complete, by doing some precise ledge grabs out ofthe leaf outside.
Note: Whichever ledge you choose to hover to, beware of troublesome keese and falling rocks!
It is still possible to skip half of the dungeon with a zombie hover in tunerless. To do so, you will need to obtain both the leaf early and the bombs early. Align yourself to zombie hover up to the 2nd floor, towards the warp pot. Zombie Hover up. Once you are above the warp pot, drop a bomb during your hover. In order to drop a bomb while hovering, pull out a bomb and then press the leaf button once the bomb is above your head, then continue mashing b to hover. Once the bomb explodes the rock and unlocks the warp pot, simply die to respawn at the beginning of the dungeon and take the warp pot to get to the 2nd floor early.
Simply jump across on the first sidle, then get to the other one. Align yourself and sidehop, jumpslash.
Using chest storage you can speed up DRC by quite a bit, by skipping the room that contains the compass chest and rats. First, make sure to pull the block all the way in the main room of DRC, so that the game remembers it has been pulled all the way (this is important). Get the 2nd small key normally and then go back to the previous room (the room with the map chest). Get Storage in that room and open the map chest to get Chest Storage. Go back to the main room. Because you pulled the block all the way, you are able to maneuver around the main room without issue (remember that you cannot climb up ledges with chest storage active).
Then proceed through the dungeon. In the room located outside with the ladder, you can climb up the wall to skip it. Then you can continue climbing up the walls so that you end up above the room with the Kargarok keeping a small key in his nest. This is because both of those outside rooms are actually the same room, but one is very high above the other. Then simply jump down (be careful as to not void-out by falling for too long at once) and continue through the dungeon normally. When you get to the room where you are supposed to fight 3 bokoblins, get crushed by the table to lose chest storage so that you can climb the ladder after the fight.
If you have the deku leaf, you can do an even faster version of the chest storage route described above. First of all, get the 2nd small key and use it. Because you have the leaf, you can get chest storage with the chest that is accross the lava pit, which contains a Treasure Chart. With Chest Storage you can jump and leaf OoB directly to the switch behind the wooden gate (make sure you have bombs before doing this, if you don't then burn the gate normally instead). Proceed just like the leafless room, by skipping the room with the compass chest. Once you get to the main room on the 2nd floor, jump and leaf to your right and land on the wall. Thanks to the deku leaf and chest storage, you can climb up the walls and reach the 3rd level early. From there you can use a water pot on a lava geyser to get to the top of the room and enter the miniboss room faster than if you had to go through the dungeon normally.
You can save 6 seconds by getting dry storage from the stairs in the miniboss room and then talking to Medli to obtain the grappling hook. The text of her giving you the grappling hook will be shortened a lot.
Slash the four ropes on the second level bridge, then wait a few seconds. Go forward then the bridge will break. When you're close to the switch, press B then jump off.
After performing one of the boss key shortcut method, you need to use the grappling hook to unbar the door. The cutscene of the door unlocking is actually composed of 2 cutscenes, and there is one frame to do an input in between them. By pressing A on that frame, it is possible to let go of the grapple target mid-cutscene. This saves time as it skips having to swing for a bit after taking control of Link back.
You can skip the Grappling Hook spot in the room before the boss key with a very precise sidehop jumpslash.
Perform dry storage on the lowest left slab by getting pushed off by the wall and immediately pull out and cancel your wind waker. When you have gotten it, open the chest on the same slab. You are now in storage. Walk up to the boss room and walk up on the right wall. If you are in the right position, Link will jump off a ledge OoB. When he does, perform a jumpslash. If the angle is correct you will now enter the boss room.
Pickup the pot on the left side of the boss door and place it on the nearby ledge near the wall. Drop down, sidehop left, and pull yourself up. Pickup the pot again and use C-up to align so that the slant of the left side of the right set of teeth on door is between the E & T in "Return". Press B to drop the pot and drop back down, then sidehop to the left and jump up to grab the ledge. Pause and use pause buffering to get to the frame where Link's feet are straight (for more information on pause buffering such ledge clips and visual aid, click here). Quickly press right on the control stick and A to drop down. Now cue a Tingle Balloon and roll to the loading zone. Once you are there, use a sidehop to get in.
Call tingle, then deminish your health to 1/4 heart. Stand on the left side of the bomb flower and align with the right side of the boss door. Do a horizontal slash to hit the bomb flower (make sure your not holding L) and hold L. Zombie hover off of the explosion, and once you are above the boss door overhang heal yourself with a red Ting. Go to either the right of left side and stand on the horns jutting out of the side. Align yourself (more specific alignment to come) and roll or backflip. If done properly you should clip through the ceiling without being crushed and either still be on top of the overhang, or have fallen down, but still remain OoB. Either way, make your way towards the loading zone and jump in.