The Wanderer’s Palace is not part of the main story and is a side quest given by the NPC Allene in Vesper Bay (Western Thanalan). The quest is given at level 50 and as this dungeon is at the level cap there is no level syncing. The dungeon is located in Upper La Noscea. Below is a boss guide for the dungeon.
This dungeon is full of the classic Final Fantasy creature the tonberry. They are everywhere. The first boss is rather straight forward. The goobbue will use a mechanic that will draw you towards it. You must immediately get away from the creature or he will hit you hard.
The second boss is the hardest, it is a flan. Every so often he will spawn adds and you must take them down as fast as possible. He will also use an attack which targets a random party member regardless of the threat list. This player must then kite the flan around the room until the tank has it back, otherwise they will die.
The final boss is the Tonberry King and he will continually spawn adds. DD players should focus on these more than the main boss. Around 20% some larger tonberries will spawn and you should ignore these. The fight is now a damage race and you should use the single target limit break on the boss and burn it down with everything you have.