I appreciate everyone who rushed in on this one, but I figured out the solution myself. (Oops, was I sarcastic there?)
If you click one of the trending topics, once you're there, there's a crumb trail at the top, and the last link in the chain is "Discussions." If you click that, you get to all of the discussions for that forum, not just the "trending" ones. I'm not sure why it has to be this convoluted. If there's a shorter path, I'd appreciate hearing about it.
Hi Amy, you might not have gotten a lot of responses posting in the forum dedicated to community help. Next time, for forum-related questions, rather use this page: http://forums.adobe.com/community/general/forum_comments?view=discussions
Thanks for that. I looked around and didn't see anything that was obvious so apparently I just didn't dig into the right heading.