This cache is being placed in association with the NoVA Chapter of the Military Association of GeoCachers (MAGC) event held nearby. You're looking for a bison tube and you will need your own writing instrument to sign the log. You will also likely need a TOTT to extract the log because it's in one of those small clear capsules inside the bison tube.
Parking is available in a parking lot about a quarter mile from GZ and you'll be walking on a paved path until you're a short distance from the cache. It could be a fairly quick find for some geocachers once you get to GZ, but I wouldn't say that it's easy. It might take a bit of searching to find it. It is available 24/7, but be alert and careful if caching at night. I recommend looking for this during daylight hours only.
If you haven't found the others in the MAGC series, they are all fairly close by so I hope you take the time to check them out.