Because I'd rather not /visit the player, I made this simple command to see where they are. It will return as "<Player> is currently in <world>"
 
COMMAND
Code:
    internal class WhereisCommand : Command
    {
        public WhereisCommand()
            : base("where", YOUR SPECIAL RANK)
        {
        }

        protected override bool Process(Player player, RealmTime time, string[] args)
        {
            if (string.IsNullOrEmpty(args[0]))
            {
                player.SendHelp("Usage: /where <name>");
                return false;
            }
            {
                var plr = player.Manager.FindPlayer(args[0]);
                player.SendInfo(plr.Name + " is currently in " + plr.Owner.Name);
                return true;
            }
        }
    }


Enjoy