From the spawn (the huge mega biome) just go ahead on the left side of this mesa biome is circle river surrounded an huge mesa mountains. Before to find the main section of this seed, you should walk past of the circle river and get the pumpkins and on the right of the mesa mountain for food because your adventure quite long-term adventure. At the end of the mesa biome, that is entrace leading inside the mountains. The first things you meet is a zombies spawner and some chest, careful with the zombie, destroy them and get your price. Moreover have another zombie spawner below the first zombie spawner it also have good loot chest too.
Seeds : Yi Fan Work in PE ver0.10.0+ or ver0.10.5