The most consistent setup currently known to clip inside the cave is to position yourself using your sword and the spots on the boulder as visuals, and then dash directly south.
With the help of an Off A Ledge Fire Boost, you can get on top of the ledge near the boulder. This is currently the most efficient way of getting there.
By doing a frame perfect bomb boost, you can get on the ledge above the boulder. This method is harder than the Fire Rod one and a bit slower as well.
You can clip on a ledge near Link's house with the help of an enemy, and use the south wall to reach another ledge just above the cave entrance, which is blocked by a Big Rock. (You will need the Energy Scroll and almost all of your Energy to reach that second ledge.) From that point, you can fall down and clip into the cave.
Since the enemy used to get on the ledge actually runs towards you and not away from you, you can simply lure him a bit and stand in that corner, use the Tornado Rod after taking damage and walk north a bit to get pushed to the right side of the torch. From that spot, just use the Tornado Rod once to get on the ledge.