“I can confirm that we had a soft opening at Sky River last Tuesday,” said David Strow, spokesman for Boyd, which is managing casino operations. Shortly after midnight Tuesday, the casino posted: “Psst … you up? We’re open,” on Facebook. The Wilton Rancheria Indian Tribe surprised the public last week with a Facebook post announcing the doors were open for its Sky River Casino, a $500 million project in Elk Grove. The first tribal casino in California’s Sacramento County opened its doors two weeks early, the tribe and representatives of Boyd Gaming Corp.