I was thinking about how the underworld levels are saved tonight, and the thought occurred to me that if I could bomb a wall that is not bombable, I could travel from one level right into another one.
This glitch may be unreasonable, but one that does not seem so unreasonable is violating boundary detection with enemy boosts, flame boosts, and random button mashing.
+-------------+-----------+-+
|9 9 9 9 9 9 9|7 7 7 7 7 7|8|
+-+ | +-+ +-+
|9 9 9 9 9 9 9 9|7 7 7 7 7|8 8 8|
| | +-+ +-+
|9 9 9 9 9 9 9 9|7 7 7 7|8 8 8|
| | +-+ +-+
|9 9 9 9 9 9 9 9|7 7 7|8 8 8 8 8|
| | +-+ +-+
|9 9 9 9 9 9 9 9|7 7| |8 8 8 8|
| | +-+-+ +-+
|9 9 9 9 9 9 9 9|7 7 7 7|8 8 8 8|
+-+ +-+ +---+ +-+
|9 9 9 9 9 9| |7 7 7 7 7 7|8|
| +-+ +-+ | | +-+---+ +-|
|9| |9 9| |9| |7 7 7| |8 8 8 8|
+-+ +---+ +-+ +-----+ +-------+
If such a glitch existed, we could enter level 9 by enterring level 8 and glitch across level 7. Or, if the glitch causes "wrap-around" by glitching to the right-most of level 8, we can go straight into 9. This would bypass the Triforce check at the beginning of level 9. From here, we could plan a glitch route and fight Ganon, or hopefully just glitch to the princess.