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 indicates a user selection of a first set of one or more items to be provided by a first entity and a second set of one or more items to be provided by a second entity. The network system can determine a route of travel for a service provider to navigate in fulfilling the request. The route of navigation can be determined based at least in part on a first set of preparation timing information associated with the first set of one or more items and a second set of preparation timing information associated with the second set of one or more items.