OP really wasn't asking about map markers, was asking about QUEST markers. Just in this case the quest marker should be at Goodneighbor, but no quest marker was provided by the mod. Probably because the author just assumed everyone knew where Goodneighbor is. I guess it should be like this, but it's hard to play because the map is huge. And even after entering Goodneighbor, i need to find which building the quest is in