Ok, I've done everything you said...with a couple of differences where my screen didn't match your description. I see the metabox in my custom post type, so that's great. The problem I'm having now is that no matter what I do, it still won't show in the side bar.
I've added a text widget to my sidebar and pasted the [rwmb_meta meta_key="mbQuotes"] in the Text tab. Nothing shows up.
I've added a text widget to my sidebar and pasted the code into the Visible tab. It shows the code and not the value of the post.
I've added a Shortcode Widget to my sidebar and pasted the code in there. Nothing Shows.
I've tried changing the mbQuotes (name of Metabox) to the actual field name within the metabox (txtQuotes) but got nothing.
I'm at a loss now.