I get the cpu load using gkrellm. You can ssh into the myth box from another linux machine, run gkrellm and get the display on the other linux box. Well, you can do it from any machine that has an X server. I think there is a windows port of gkrellm too, so I think it is possible to run gkrellmd (just the daemon) on the myth box and connect to it from gkrellm on windows to display the stats, but I haven't actually tried it.

And I got my stats via top while ssh-ed in to the machine I was measuring.