Okay, I swear this is the last document conversion script I'm writing this year. I've been on a bit of a rampage to move all of my life in Emacs Org-Mode and converting all of my Tiddlywiki notes into Org mode has been on my list for a while. Thankfully both formats are pretty simple so the script was fairly straightforward.
You can find it here, simply fill in the folder locations and give it a run.
A heads up. If you're merging the newly generated Org notes into an existing directory, do a dry run in a dummy folder first then compare the dummy results with your existing Org folder. You need to ensure you won't overwrite any existing files(the script doesn't do any clever checking).
You can do something like
comm -12 <(ls ~/Documents/OrgFolder) <(ls ~/Documents/DummyFolder/org)
to run an intersection on the two filesets.