I understand that the 2nd Hatteras lighthouse built in 1868 was built substantially inland from the original 1803 lighthouse site. How far inland was the 1868 construction site?

The lighthouse was moved 2,900 feet in 23 days and now lies 1,500 feet from the seashore, its original distance from the sea. So the 1868 lighthouse was 1,500 feet from shore.

Its within walking distance of the new one and labeled as such and easy to find.

Don't know, but I can tell you that in 1980 it was 1/4 mile from the ocean. In 1998, about 100 yards. The dunes you now see, where not there in 1868.