After much futzing around for two days, I think I got the bulk of my data back. I will now do a *.sqz backup after *every* data entry session.
When I printed out the Project Summary report, I noticed that all of my v_*book files were pointing to my old Family Gathering directory. So, I dropped the appropriate files into the old FG directory. This still didn't work perfectly, but at least it got me closer. I also found that one of my individual dbf files was missing the *.cdx and *.fpt files that went along with it. I patched together from various backups a semblance of normalcy, and was able to get even more of my data back.
The only data that now seems to be missing is my source links to my evidence. I'm sure there's a way to rectify this situation though.
Lucky I'm stubborn, or I would have been tempted to start afresh with a new genealogy program.