Dired+ just uses your
recentf-list of files and directories. It is library
recentf.el that controls what file and dir names to record there.
For that, library
recentf.el provides several user options, which filter out certain file and dir names, etc. That's no doubt what you're running into.
Your second question isn't clear to me (and you really should pose only one question per question). Perhaps you're asking how you can echo the list of recent directories to the echo area (same space as the minibuffer, but for output, not input).
For that, you can use this command:
(defun foo ()
(message "Recent dirs: %S" (diredp-recent-dirs nil)))
(If you want a different sort order, let-bind variable
diredp-default-sort-arbitrary-function to a function that sorts the way you want.)