|Yea 200 feet could be pushing it a bit. |
Normal 802.11 wireless devices are rated at 300 feet w/ a clear line of sight. If it's going through walls and picking up interference, the actual limit is more like 100 feet.
Also speed will be a concern. Even with a decent signal strength, wireless is only 54Mb/s half duplex, and you're lucky to get about 20Mb/s of actual throughput. Compared to the 100/1000 Mb/s you'd get from a wired connection.
Might also do a site survey - are there alot of other business nearby? If they have wireless connections running on or around the same channel, they'll slow your connection down even further.
If you do the wireless setup, should also look into some directional antennas & focus them at each other to help w/ signal strength.
Is running a cable out of the question?? You might also look into a fiber run. An Lx fiber module can run up to 5km. Might be a little more expensive though (say, $2000-3000 for 2 routers / lx modules / cabling) & then whatever costs to actually run the thing.
You could also contact the telco & get prices for a leased line between the two offices - no idea on pricing, though.