I chose the "Schiphol- Amsterdam Centraal- Maastricht" route, so that I can take a stroll through Amsterdam.
It was my first time there and having 3-4 hours to kill I visited what I could before taking the train to Maastricht.
Although the Amsterdam Centraal-Maastricht is a direct train, one should pay attention to the wagons since half of them go to Heerlen and half to Maastricht.
Normally, the ticket controller will inform you whether you are in the right wagons or not.