Hey. I can confirm that PTR build 1.30.1 doesn’t let you play over LAN. We could see each other’s games, but couldn’t connect. I don’t believe LAN would work on the other PTR builds, but its worth a try. If anyone would like to try and get back to us, that would be great as the PTR builds are convenient.
That being said, I made a thread over here: For those who want to play Classic Warcraft 3 - #2 by wc3tutor-1926
This thread details what you need to play the classic client.