Right now I'm restoring the new drive back to Jan 2014, the time before last that it backed up before upgrading to Mavericks. Hopefully that will work acceptably. I can recover nearly all my data from the repositories I created before migrating, the exceptions being latest info from Firefox and the emails received in the last 2 months.
I'm not sure yet how to tackle the emails - really don't want to lose some of them - but I'll probably try the archiving again. I may also see if there's a more rudimentary, yet simpler way to save them.
And I'm becoming increasingly sympathetic toward replacing this computer. Presently typing from the little Philips Freevents I bought last year. In the end Mint Debian was removed, because it's relatively slow and clunky compared to Linux Lite, and I've returned to that.