Casino officials intend to expand in a few more years with a permanent gaming hall, a 150- to 200-room hotel and additional restaurants. The expansion is driven by a competitive threat to the south that will end River Rock’s monopoly on Indian gaming in Sonoma County. The Federated Indians of Graton Rancheria have started their long-stalled casino-resort in Rohnert Park just west of Highway 101, expected to open by late next year.