Use the Ball & Chain to destroy the lookout tower next to the fence, transform into a wolf, and walk through the gap. Then on the second fence, go over to the right side (GCN) and just try and wedge your way through it.
After trigger the Bulblin archer cutscene, run over to the left (GCN) side of the barricade and wait for a little while until one of the boars runs into the wall, launching the Bulblin riders onto the wall. As a wolf, get near to the wall and use an area attack to target the riders. Walk back a few feet from the wall and use the area attack to super jump onto the wall.
The trigger that loads the path to Arbiter's Grounds doesn't exist until you defeat King Bulblin and break through the fences with a boar.
It is faster by 3.5s to dash up to the broken wall before the main part of the camp, then perform Map Glitch and LJA from the corner of this wall to the hill OoB. From here you can jump attack diagonally to the King Bulblin trigger. During daytime the bulblin archer will shoot arrows at you however the setup avoids this issue. Finally when 100% used to have bombarrows at this point in the run (fixed EMS route) you could bombarrow the boar through the wall to release the HP for later, however now in 100% you cannot bombarrow the boar however it is still faster to this this, furthermore the bulblin doesn't shoot at night.
1) Perform Map Glitch (this can be done later as climbing wall to combine it with the transform however you won't have time to unplug for consistentcy
2) Dash to the broken wall and climb up the left edge
3) Walk forward a little then transform
4) Walk forward towards the edge, then sidehop right 3 times, making sure the bulblin shoots during the sidehops
5) Aim at the corner of the hill and LJA instantly over
6) roll forward and line up so your jump attack will hit the bulblin trigger
When you enter the Bulblin Camp, immediately perform the Map Glitch and backwalk off the solid ground. Do a jumpslash while falling to give yourself forward momentum. If done right, you will clip into the cutscene trigger, which will reposition you above ground.
Instead of making the whole trip through the Bulblin camp while fighting you can lja on top of the Camp to trigger the cutscene and skip the small key saving ~8 seconds.
The LJA is rather precise though and the window for the jump is pretty small.