OCEANSIDE, CA—Developers are scrambling for the dwindling amount of developable land in Oceanside, which represents space that previously hadn’t been touched before the last cycle. Among that space is Rancho del Oro, a master-planned community here, in which Presidio Residential Capital and Cornerstone Communities have broken ground on Pacific Ridge, a 30-acre, 317-unit gated development being built on the last remaining land within the community.