Can't believe I forgot Lewis Mtn! That was the very first place I stayed in SNP way back in the 1960s when my parents brought the family there in the station wagon and pop-up camper! I must be getting old if I'm forgetting Lewis Mtn.
Indeed, there is a campstore. And when you're passing by the campground on the AT, the flushies are nearly right next to the trail! You can even rent towels there for showers.