... proved to be more of a challenge than I thought it would be!
Before the upgrade to vB4, many of our users used the "Go" button in the Quick navigation at the bottom of a thread to get back to the containing forum, which is now not an option. I figured it would be easy to add a link that leads back to the forum the thread is in, but I've had no luck finding the right variable to use - I've tried many different combinations in both showthread and forumjump.