As others have mentioned in milestone cache descriptions, this is probably the most significant milestone, since it indicates that the cacher is truly dedicated to this kind of crazy sport. I have been Goldielox's partner on most of her finds, as we cached across New Hampshire and the United States and in several other countries, arguing all the way about the relative merits of Garmin and Magellan. For the most part, Goldielox is a fearless cacher, except for the spiders, so she brings me along to shoo them away and clear out the webs.
Congratulations, Goldielox, its been a joy caching with you - now let's go get the next 1000!
The cache is located in a small "island" park in Concord. Bring your own pen, and tweezers will be helpful.