I have both a wired and wireless network that I set up in my house. I have two separate wireless routers and an ‘extender’. I can get decent signal out to the woods behind my house but that’s not 200 yards away. My neighbor, whose house is probably that far away, says he can see my routers in his computer but I have my network access encrypted so it can’t be hitched. Thus, a wireless signal 600 feet straight can be done with a basic wireless router but your signal strength that far away will be weak. Could you run a wired cable out to where you want a hook-up? If you have power out that far, you could run an ethernet cable out, hook another wireless router to the end and then have a good radius of coverage around that spot. On the other hand, you can manipulate the ‘field’ of coverage by using antenna of different length and pointing them in a particular location. The wireless coverage field from a router is not a perfect sphere…
I used to work at a facility with buildings spread over 300+ acres. All our networking there was wireless – we ‘beamed’ signal from one location to another with equipment designed for just that. I don’t think they’re ‘cheap’ though!