It’s been about three years since the groundbreaking ceremony for Riverstone, one of two massive planned housing developments being built off Highway 41 in southeast Madera County. Considering the estimated scope of the project — 6,578 homes on about 2,000 acres — it may not be completed for 30 years or more. But Riverstone and the other big Madera County development to the north along 41, Tesoro Viejo, aren’t just about home building.