If you are planning to drive from Grand Case to Philipsburg for dinner (i.e, Chesterfields, etc.) that drive would be fine after dark. Just don't stop in between. I wouldn't go the other way (through Marigot) after dark. As far as walking from the GCBC to whatever restaurants are open in Grand Case I would have no problems with this, and have done it in the past. Just watch out for traffic behind you!