With some islands just big enough to stand on and others nearly as large as the center of Stockholm, the archipelago was once a rough and remote home to farmers and fishermen. Long an inspiration to Swedish artists and writers, the area changed in the middle of the last century, when tens of thousands of ordinary Swedes began to summer here. Now, as expensive year-round homes replace seasonal shacks, Stockholmers are discovering the area's off-season pleasures and property values are skyrocketing.