How important are hiding functions?  

Do you know that every time makeNewWidget is called, those functions are re-created?  This is why protoypal inheritance is so much faster than the module pattern in JS.  Each function is only created once.

Why not use _privateMethodName or something?

In general, I discourage the module pattern in JS.  It's slow.  People don't understand that JS is a scripting language and that they are re-creating those functions for every object.

If you are desperate to hide things, create the functions outside the makeNewWidget, don't use a closure, and instead make them take arguments.  You'll notice this is what a lot of JMVC code looks like - helper functions on top.