Bypass the Door of Time without the spiritual stones Edit
Get against the wall. Press Z 2 times to make sure the camera is perpendicular to the wall. Turn around quickly (straight back, not at an angle), and try not to move forward either. whether you do or don't move forward, press Z and strafe into the corner so that when you align it in the next step, the angle and positioning is the same every time.
Line up the pointed part of your swords handle (the left and highest part of the handle) on the sword icon, with that crack between the 2 wall textures.
Then hold Z, and then leave C-UP view while still holding Z.
NOW HERE IS SOMETHING HELPFUL Edit
Move very slightly to the right while still being flesh against the wall. This small space keeps Link from moving forwards along the front of the DOT when he rolls. He stays flat against the corner.
Now, very lightly tilt the control stick diagonally to the bottom left. If the 'A' button doesn't read JUMP then you are good (as long as it's tilted a bit). Press A and then as the roll starts, you can now move the control stick all the way diagonal as far as it goes and mash A. Link will roll into the corner and if you time the sidehop right then you will get through it almost every time.
Whether you get far enough after clipping to stay in the wall, or if you get spit back out depends on how late you wait to jumpslash after you clip through the wall. So don't jumpslash too early or you won't get through (or stay in), but if you do it too late then you will die. At least if you get spit back out, you still have the proper angle and can keep holding Z and just use a bottle to sheath your sword. Then you can do it again. This is faster than dying at least and having to set it up again (as well as the falling time, and the time it takes to run back over there from the entrance).
With practice and a few precision tips, it becomes a pretty easy trick.