A computer system can estimate preparation times associated with items offered by a plurality of entities to manage a service over a given geographic region. The computer system can receive, from a user device of a user, a request that includes a selection of one or more items offered by one or more entities near the service location. The network system can determine an optimal route of navigation for a service provider to navigate in fulfilling the request. The route of navigation can be determined based at least in part on timing information associated with the one or more items selected by the user. The timing information can be determined based on historical data and/or real-time data.