Membership plugin - allowing free access to articles

I would like a way to expose older posts for free viewing. I use Categories to protect posts (all Categories are protected) and the More Tag to expose teaser text to non-subscribers. For older content, I would like a non-subscriber to click on the link following the teaser content and read the entire post. I've tried numerous combinations of features in Access Levels. Lots of ways to stop readers from reading posts, but haven't found a way to expose older posts to readers. What am I missing?