[mikedave]

Any commands (sm or not) that will show me whos logged into the server via something like rcon_address, or any other commands or things I can do to see who's doing stuff to the server externally?

[Dravu]

It depends on how they do it. They can easily login, send a command, and log back out in less than a second and you'll miss it. If they're using HLSW and hit the Get Log button, then you can run this command to see who's in:
logaddress_list