@Terry
Haven't played the game, so I have no idea. Do take into consideration that you might just not be able to do it on a modern system.
I've encountered a game (Heroes of Might and Magic 3) where the original CD just doesn't let me install it in modern Windows because it doesn't understand something in the configuration. I literally have to install it in a WinXP VM, then copy the files over.
@Terry
If Vegas 1 MP depends on some Ubisoft server, that's probably been long since closed. If it's just LAN, idk.
@Terry
Then maybe it has LAN... or there exists a private emulated server thing somewhere.