Are you all up to a small side adventure that is right near where we are going?
Located in Prospertown 400 feet from the intersection is Mile Marker 39.63 of the Lawrence Line. It is the western boundary of Great Adventure. The marker is there! It is a semi newer one, but a Lawrence Line marker all the same. By newer I mean it is cement. I have detailed instruction and even a survey map of the area you may be interested in. Also, I have a photo of the marker, a Cowards/Prospertown Late 1700's map, a 1814 Prospertown map, and a survey report from 1817 with a map showing "chain lengths". They used actual chains to measure distance back then.
I will email a copy tomorrow to all that are definitely going if anyone is interested. The maps are copies and not perfect, but you may find something of interest in them. I will pass along the GPS coordinates of the marker, but I believe them to be inaccurate. They were taken by an old "Scout" model. But I have calculated the actual coordinates, and found the location on the map where it is. Plus the survey map shows it's location exactly.
Guy