Port-hinterland flow optimization is a long-standing challenge, yet decades of transport engineering and economics modelling still fail to fulfil the synchromodality promise. Past attempts focused on extended gateways (or transferia) as a remote drop-off, cargo consolidation, and pick-up points for containers outside the port periphery. Although these experiments demonstrated the functional optimization potential, none scaled into economically viable synchromodal consolidation hubs. Whereas extant research focuses on logistical, technological, and economic aspects of synchromodal consolidation, we argue that collaborative enablers need more attention. This chapter develops the GAP-N model to tackle the techno-economic and social barriers towards corridor integration. The latter include actor interdependencies, cultural, and organizational interoperability. The GAP-N is an ecosystem-based framework combining extended gateways with digital platform technology and stakeholder governance principles. This combination allows port communities to create roadmaps to align supply chain actors and tackle the technological, business model, and mobilization needs for port-hinterland flow optimization at corridor-level.