Once you get to the point in the storyline where you get the chests in the chieftess' hut at Woodburrow that the person refills every day, open the chests and collect the coins. Go to the "Level Select" screen and enter a level. As soon as possible, open the menu and return to Woodburrow. When you get back into town the chests will already be refilled. Repeat the process as many times as desired for unlimited coins. This results in about 440 total coins and takes 30 to 45 seconds to repeat.