Fort Nonsense was built by Washington's army when whey were encamped in nearby Jockey Hollow during the winter of 1777-1778. Legend has it that the fort was deemed "Fort Nonsense" by the soldiers who built it, because they thought its purpose was to keep them occupied and it had no strategic value. Historians discount this, as there is no written record of the name Fort Nonsense used before the 1830's.
In reality, the fort was one of strategic importance, and was built at the order of Washington himself. His order directed a Lt. Col. Olney and his detachment "and the Militia now here Guard the Stores of different kinds. Strengthen the Works already begun upon the Hill near this place, and erect such others as are necessary for the better defending of it, that it may become a safe retreat in case of Necessity" (I think that instead of chopping down cherry trees and throwing coins over rivers, George should have attended his 2nd grade English class more often ;) ).
Today nothing remains of the original fort, but stones mark the location of the walls and you can see the commanding view that made this hill strategically important.
To find the cache, go to the object located at the published coordinates. At the base are a year and serial number. Add the 4 digit year to 4045753 to obtain the N coordinate. Add the 5 digit serial number to 7353704 to get the W coordinate.
Note: If your math indicates more than about .17 mile from stage one to the cache, then you misread one of the digits on the serial number (see some of the logs). There really should be no need to get in your car and drive to the final stage.