Espruino on ESP8266

So which UART is the one you'd generally use if you had the AT firmware on the ESP8266?

I'd strongly suggest you enable the command prompt on that one at least initially, as it'll make it a million times easier to test and debug the wifi networking capability, as well as to use Espruino with the Web IDE.

When that's done you can just run this to get your telnet shell:

    require("net").createServer(function (connection) {
       connection.pipe(LoopbackA);
       LoopbackA.pipe(connection);
       LoopbackB.setConsole();
    }).listen(23);

Obviously that could be built-in, but it's a good start.