There are a lot of things to consider before you just go throwing goats on your land.
It sounds to me like this land is not yet fenced. Some of it is probably pretty hard to fence because of all of the undergrowth and garbage. If you've never tried to keep goats on one side of a fence this is not the property to try to learn on LOL. It sounds to me like you would have to do a great deal of work just to clear a lane for fencing.
Also, there is some stuff that goats can't eat. If you don't know what those plants are and if you have them on your property or how to get rid of them if you do, you may end up with sick or dead goats.
Also, goats are meandering browsers. Unless they find something absolutely delicious, they will eat a few bites here, a few bites there, and then wander on to something else. They really don't obliterate plant material until you stock them at a very high density. You have to pack them in there, but you have to be ready to move them on quickly because once you reeeeeeally pack them in someplace they will literally eat everything.
So, 500 goats may not be your answer.