How do you win Goats & Goblins?

About Goats & Goblins, from BoardGameGeek:

Those pesky goats have escaped again and are now bleating for your help from inside a treacherous cave! You and your fellow goblin herders must go down and retrieve them, but you soon spot mysterious gold, precious gems, and lovely trinkets in the shafts below. New plan: the goblin who can retrieve the most treasure from the risky depths wins! But be careful - going too deep may cause too many Cave-Ins and force you to drop your treasure as you flee, leaving it unguarded for the saboteurs to take. Goats and Goblins is a push-your-luck game where you will attempt to collect treasures, goats, and goblins from the mysterious cave before it collapses. You will take turns leading expeditions below the surface, inviting other players to join you or stay behind. If your mission is successful, the exploring members will gain valuable cards to divide. Failed expeditions will give cards to the players who did not explore the cave. Some cards can be played to support or hinder expeditions. It's game over when the Cave deck is gone or almost gone (less than 3 cards remain). When the game ends, count the gold on your unplayed cards. The goblin with the most gold wins. -description from the publisher