score:3
Safety is not an issue.
The problem is that you are far from the city center without a direct metro (maybe bus?) to where everything is; I don't think the night life is that great in the area.
There's a train (metro, I'm not certain), the L train that gets you to Saint Lazare Train Station in about 30 minutes.
The Saint Lazare Train Station is as good as any starting/end point for your daily visits to Paris.
There are also bus lines, but I can't navigate the RATP site well enough to help you.