Crime, late-night parties and fires, dumped cars, off-road accidents and promiscuous shooting are just some of the headaches local deputies regularly encounter in the Greenhorn Creek area of Nevada County.They're getting fed up. "We have had several reports of rapes, people not wearing their helmets, riding too close, accidents, beer bottles everywhere," Nevada County Sheriff's Cpl. Walt Jones said. "We're called out there many times over the year."A memorial cross and flowers at the edge of a steep cliff at Greenhorn Creek for Brandon Alcala - a 19-year-old Grass Valley man who died from injuries he suffered while four-wheeling there …