This project analyzed, designed, and optimized the delivery-network extension for PPL. After a new high-capacity sorting hub went live, routing complexity rapidly increased, making effective manual planning intractable. The approach combined a discrete-event simulation (DES) digital twin with optimization methods such as Integer Linear Programming to test, tune, and validate routing strategies on real operational data. Insights from the optimization runs were fed back into the DES model to verify performance under realistic constraints and edge cases. This closed loop produced concrete, defensible routing and flow-allocation decisions that were delivered to management as actionable implementation plans.