This is a case study in the use of product-line architectures (PLAs) and domain-specific languages (DSLs) to design an extensible command-and-control simulator for Army fire support. The reusable components of our PLA are layers or "aspects" whose addition or removal simultaneously impacts the source code of multiple objects in multiple, distributed programs. The complexity of our component specifications is substantially reduced by using a DSL for defining and refining state machines, abstractions that are fundamental to simulators. We present preliminary results that show how our PLA and DSL synergistically produce a more flexible way of implementing state-machine-based simulators than is possible with a pure Java implementation.