The challenge is to find at least 1000 - 1.5 Star Terrain caches. They can be any difficulty or even only 1 difficulty, as long as there is 1000 caches total.
For example, You can have 1000 - 1.5/1.5s, or 3 - 5/1.5s, 5 -2.5/1.5s, 985 - 1.5/1.5s, 7 - 5/1.5s, and 0 of the rest equaling 1000 total. You must show proof of qualifications by referencing your profile, bookmark, screen shot, etc.
Cache IS at the posted coordinates, Geocachers may sign a challenge geocache's physical log at any time. However, the challenge cache may be logged as found online only after the log is signed and the challenge tasks have been met and documented.