Your organization operates Compute Engine instances in three different regions: us-east1, us-west2, and us-central1. Currently, there is a Cloud Interconnect physical connection established on the East Coast of the United States, specifically in the us-east1 region, which includes a single VLAN attachment and a Cloud Router. You need to devise a network design that ensures high availability and maintains connectivity to all VPC subnets, even if one region experiences downtime. Given the need for cost-efficiency, how should you proceed?