Implementing TSP or vehicle routing in Drools Planner 5.4.0.Beta2 and earlier was difficult. But starting from 5.4.0.CR1, such use cases are easy and far less code to implement. And they are compatible with real-time planning.
Just take a look at the Traveling Salesman Problem (TSP) demo. It shows adding cities in real-time and demonstrates how easy it is to change the constraints:
Coming soon: a vehicle routing example and even better scalability.