First and foremost, know that this cache was placed with permission, and the parking waypoint is kosher. You'll be entering Prince William County land, though its surrounding environs are...well, atypical.
This is a 4-stage multi-cache, with a twist. You're looking for three key words. When placed into the checker below in order (shortest word to longest word), you'll be gifted with the secret hiding spot. Certitude frowns on spaces. Smashthosecluestogether. so if the words were cat house tree the solution would be cattreehouse
You are entering Mattaponi Territory. While it is doubtful that a Patawomeck tribesperson could even understand the significance of such a spot - given their spelling habits - Mattaponi should take precautions. While we've deployed every spider in a three square mile area, there is little physical protection of our artifact. Well...except a little elevation. 
The Battle of Cockpit Point, the Battle of Freestone Point, or the Battle of Shipping Point, took place near here on January 3, 1862, as part of the blockade of the Potomac River during the American Civil War.
Union ships approached the point again on March 9. A landing party from the USS Anacostia and the USS Yankee destroyed abandoned Confederate batteries at Cockpit Point and Evansport, Virginia, and found the CSS Page blown up. The Confederates, in keeping with their general tactic of withdrawal from the sea coast and coastal islands, had abandoned their works and retired closer to Richmond, after effectively sealing off the Potomac River for nearly five months. Prince William County is in the process of establishing the Cockpit Point Battlefield Heritage Park.
You can validate your puzzle solution with certitude.
