Round up time for Tres Hermanos Ranch?

If you are somewhat new to the area you may not have heard of Tres Hermanos Ranch, once the country ranch getaway for three rich Los Angeles guys.
The 2,450-acre property is in upper Tonner Canyon, beyond the former Firestone Scout Reserve and can only be reach via private roads. Tres Hermanos and the Scout Reserve are both owned by the City of Industry.
Since the 1970s, the tiny 12-square-mile City of Industry has gobbled up prime land in San Gabriel Valley and much of Tonner Canyon, including