So - mixed results.
The install worked great. I downloaded, installed, but DID NOT launch the game. I did launch the launcher (so that it was patched). Everyone was able to get going with one who had to restart to get UE3 to trigger.
The server worked reasonably well. One player had some CPU issues (or maybe RAM? there was framerate lag, but the other 16-20 people had no issues).
The issue was that the LAN server was open to the internet. We had someone known as Player292 join the server after about 15 minutes of us all just slamming back and forth and he wrecked it. Of the winning 12,000 points he was something like 9000 of them. He was the only one who killed any buildings. I had no idea how to get a password onto the server; or how to initiate a vote (it was greyed out) so we couldn't get rid of him. That resulted in people more or less losing interest as, well, it was a slaughter.
That said, beyond that for anyone who is looking to use it as a LAN, that should work no problem! The theory is sound and people had fun until 292 showed up.