Well, these things often happen this way for me. Just after I posted this, I stumbled across a menu that showed me the real location of the caches. I cleared out the old files that were reasonably new and close to the dates I've been working on. The audio is synchronized now!!
Hopefully someone else stumbling across this thread will find this useful. I found the locations pointed to in the Edit->Preferences->Scratch Disks... menu. I cleared out the Media Cache files that were possible candidates.
