Hmm... This is interesting. You must have gone through a few dungeon, which I'm not sure of. You do need a series of Dungeon items, and I"ll continue to find a list of the ones you need in order to progress through Gerudo training grounds
, which is found in Gerudo fortress, if you don't know.
I know that you need epona ot get to Gerudo fortress so that's checked off, and I"ll go and check to see what items you need in order to progress through the Dungeon.
Aha, you need the membership card to get into the Training grounds, which you need the longshot, whic you find in the water temple. But that still doesn't explain if you can get it before the fight of morpha, hmm I"ll check ZD;s guide to it.
Ok so you need the Bow,WE all know that you'll need a sword,you need the longshot(maybe even though hookshot), ya need the ocarina( if you wanna use the scarecorws song for help),you need the silver gauntlents, stop, can you possibly get the silver gauntlents before morpha?