Got a little further. I borrowed ConsoleDocument from Snow (Alessio's work) and am trying to use it instead of JConsole. I can start up a lisp in it. However
a) It reads and prints the result of one command, prints the prompt, and hangs on the next.
Ah well, this is what snow itself does when I try to launch ConsoleDocument.main. So I will take that up with Alessio.