The Bulletin Board appears after completing three bundles.
Completing the Bulletin Board bundles improves the player's friendship rating with every non marriage candidate villager by two hearts. The morning after, Mayor Lewis will send you a mail saying that all the villagers have been getting items they have wanted for years that they posted on the bulletin board in the community center. He proclaims his gratitude of all your hard work.
The Vault becomes available after completing four bundles. Each bundle in the vault simply requires gold to complete, and the item slots are replaced with a large purchase button. Pressing 'purchase' will complete the bundle and deduct the gold from the player's total, provided they have enough.
Completing the Vault bundles, costing a total of data-sort-value="42500">42,500金, repairs the Bus on the road between your farm and Pelican Town. Taking the Bus grants access to the Calico Desert.