I want to explore a couple of small ancestral near Sittard, Netherlands where family emigrated from and wondering if renting a car is the way to go? Traveling from Brussels to these villages, stay for two nights, then on to Amsterdam. It looks like there's bus service in these villages through Arriva but given the short time trying to minimize hassles.
You only mentioned Sittard specifically and this is connected by train from Brussels. And you did not mention any others so no one can help give you a definite answer on how to get to the them. So, why not just rent the car?
You are familiar with the public transport planner 9292.nl? Buses might be less inconvenient than you fear.