The use of mobile agents for data fusion in wireless sensor networks has been recently proposed in the literature to answer the scalability problem of client/server model. In this article, we consider the problem of calculating a near-optimal route for a mobile agent that incrementally fuses the data as it visits the nodes in a distributed sensor network. The order of visited nodes affects not only the quality but also the overall cost of data fusion. We propose two heuristic algorithms that adapt methods usually applied in network design problems in the specific requirements of sensor networks. They suggest the proper number of MAs that minimizes the overall data fusion cost and construct near-optimal itineraries for each of them.