Michael Fogleman has written an Emacs major mode called tid-mode, which is for editing TiddlyWiki .tid files. It is derived from text-mode, uses the useful minor modes org-struct and subword, and updates the modified times when you save a .tid file.

He also wrote two helper functions for using TiddlyWiki in Emacs. The first opens a tiddlers directory in Dired; the second opens TiddlyWiki in the browser.

(defun open-wiki ()
  "Opens a TiddlyWiki directory in Dired."
  (interactive)
  (dired "~/Dropbox/wiki/tiddlers/"))

(defun browse-wiki ()
  "Opens TiddlyWiki in the browser."
  (interactive)
  (browse-url "127.0.0.1:8080/"))

This latter function may require specifying a browser:

(setq browse-url-browser-function 'browse-url-generic
      browse-url-generic-program "chromium")

You can bind either of these functions with the global-set-key function:

(global-set-key (kbd "C-c w") 'open-wiki)

At the moment, these are not integrated into tid-mode.