http://digitalpaint.planetquake.gamespy.com/docs/server_guide_win32.htmlthere's a guide for setting up a dedicated server (on windows, but instead of creating a shortcut like in windows, you could create a shell-script to start up the game with the same parameters etc.).
If you don't want to allow internet users to access your server, simply don't open the port your server uses in your firewall. So, if you use the standard port of 27910, only allow internal traffic and don't open that port to the internet.
I don't really understand what u mean with you "don't want any userids for the global server stuff", but if you mean you don't want your kids to have to login before joining the server, you can include the following line in your server.cfg:
"sv_login 0"
I hope that answers your questions, have fun playing!